Display device, display module, and electronic apparatus

Abstract

The invention provides a display device, a display module and electronic equipment. Provided is a liquid crystal display device having a high aperture ratio. Provided is a liquid crystal display device with low power consumption. One embodiment of the present invention is a display device having a display unit and a drive circuit unit. The display unit includes a liquid crystal element, a first transistor, a scan line, and a signal line. The driving circuit portion includes a second transistor. The liquid crystal element comprises a pixel electrode, a liquid crystal layer and a common electrode. The scanning line and the signal line are electrically connected with the first transistor. The scanning line and the signal line respectively comprise a metal layer. The structure of the first transistor is different from that of the second transistor. The first transistor is electrically connected to the pixel electrode. The first transistor has a first region connected to the pixel electrode. The pixel electrode, the common electrode and the first area have the function of transmitting visible light. The visible light passes through the first area and the liquid crystal element and is emitted to the outside of the display device.

Description

[0001] This invention application is a divisional application of the invention patent application with international application number PCT / IB2017 / 057151, international application date November 16, 2017, application number 201780070861.9 which entered the Chinese national phase, and entitled "Display device, display module and electronic device". Technical Field

[0002] One aspect of the present invention relates to a liquid crystal display device, a display module, and an electronic device. Another aspect of the present invention relates to a method for manufacturing a liquid crystal display device.

[0003] Note that one aspect of the present invention is not limited to the technical fields described above. Examples of technical fields encompassing one aspect of the present invention include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and methods for driving or manufacturing these devices. Background Technology

[0004] Transistors used in most flat panel displays, such as liquid crystal displays and light-emitting displays, are made using silicon semiconductors, such as amorphous silicon, monocrystalline silicon, or polycrystalline silicon, disposed on a glass substrate. Furthermore, transistors using this silicon semiconductor are also used in integrated circuits (ICs).

[0005] In recent years, the technology of using metal oxides exhibiting semiconductor properties in transistors to replace silicon semiconductors has attracted much attention. Note that in this specification, metal oxides exhibiting semiconductor properties are referred to as oxide semiconductors. For example, Patent Documents 1 and 2 have disclosed technologies for using zinc oxide or In-Ga-Zn oxides as oxide semiconductors to manufacture transistors and using these transistors as switching elements of pixels in display devices.

[0006] [Preliminary Technology Documents]

[0007] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2007-123861

[0009] [Patent Document 2] Japanese Patent Application Publication No. 2007-96055 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] One objective of this invention is to provide a liquid crystal display device with a high aperture ratio. Another objective of this invention is to provide a liquid crystal display device with low power consumption. One objective of this invention is to provide a high-definition liquid crystal display device. One objective of this invention is to provide a liquid crystal display device with a narrow bezel. One objective of this invention is to provide a liquid crystal display device with high reliability.

[0012] One objective of this invention is to provide a low-cost and highly producible method for manufacturing liquid crystal display devices. Another objective of this invention is to manufacture liquid crystal display devices using large substrates. Finally, another objective of this invention is to simplify the manufacturing process of liquid crystal display devices.

[0013] Note that the description of these objectives does not preclude the existence of other objectives. One aspect of the invention does not require achieving all of the above objectives. Objectives other than those described above can be extracted from the specification, drawings, and claims.

[0014] means of solving technical problems

[0015] One aspect of the present invention is a display device having a display section and a driving circuit section. The display section includes a liquid crystal element, a first transistor, scan lines, and signal lines. The driving circuit section includes a second transistor. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The scan lines and signal lines are electrically connected to the first transistor. The scan lines and signal lines each include a metal layer. The structure of the first transistor differs from the structure of the second transistor. The first transistor is electrically connected to the pixel electrode. The first transistor has a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region have the function of transmitting visible light. Visible light passes through the first region and the liquid crystal element and is emitted to the outside of the display device.

[0016] Here are examples of first and second transistors having different structures. For example, a first transistor may be a bottom-gate type while the second transistor is a top-gate type. Another example is a structure where the channel region of the first transistor contains metal oxide while the channel region of the second transistor contains silicon. Yet another example is a structure where the channel regions of the first and second transistors contain the same material but have different crystal structures.

[0017] The scan line preferably has a portion that overlaps with the channel region of the first transistor.

[0018] The first region preferably contains metal oxides.

[0019] The channel region and the first region of the first transistor may contain metal oxide. In this case, it is preferable that the metal oxide included in the first region contains one or more of the metal elements contained in the metal oxide included in the channel region.

[0020] One aspect of the present invention is a display module comprising a display device having any of the structures described above. The display module is equipped with connectors such as flexible printed circuit boards (FPCs) or TCP (TapeCarrier Packages), or with ICs mounted using COG (Chip On Glass) or COF (Chip On Film) methods.

[0021] One aspect of the present invention is an electronic device comprising: the aforementioned display module; and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and operation buttons.

[0022] Invention Effects

[0023] According to one aspect of the present invention, a liquid crystal display device with a high aperture ratio can be provided. Additionally, according to one aspect of the present invention, a liquid crystal display device with low power consumption can be provided. Furthermore, according to one aspect of the present invention, a high-resolution liquid crystal display device can be provided. Furthermore, according to one aspect of the present invention, a liquid crystal display device with a narrow bezel can be provided. Furthermore, according to one aspect of the present invention, a liquid crystal display device with high reliability can be provided.

[0024] According to one aspect of the present invention, a method for manufacturing a liquid crystal display device with low cost and high mass production capability can be provided. According to one aspect of the present invention, a liquid crystal display device can be manufactured using a large substrate. According to one aspect of the present invention, the manufacturing process of a liquid crystal display device can be simplified.

[0025] Note that the description of these effects does not preclude the existence of other effects. One aspect of the invention does not require achieving all of the above-described effects. Effects other than those described above can be extracted from the description, drawings, and claims. Brief description of the attached figures

[0026] [Figure 1] is a cross-sectional view showing an example of a display device.

[0027] [Figure 2] is a top view and cross-sectional view showing an example of a display device.

[0028] [ Figure 3 [This is a perspective view showing an example of a display device.]

[0029] [ Figure 4[ ] is a cross-sectional view showing an example of a display device.

[0030] [Figure 5] is a cross-sectional view showing an example of a transistor manufacturing method.

[0031] [Figure 6] is a cross-sectional view showing an example of a display device.

[0032] [ Figure 7 [ ] is a cross-sectional view showing an example of a display device.

[0033] [ Figure 8 [ ] is a cross-sectional view showing an example of a display device.

[0034] [ Figure 9 [ ] is a cross-sectional view showing an example of a display device.

[0035] [Figure 10] is a cross-sectional view showing an example of a method for manufacturing a transistor.

[0036] [Figure 11] is a cross-sectional view showing an example of a method for manufacturing a transistor.

[0037] [ Figure 12 [ ] is a cross-sectional view showing an example of a display device.

[0038] [Figure 13] is a cross-sectional view showing an example of a method for manufacturing a transistor.

[0039] [ Figure 14 [ ] is a cross-sectional view showing an example of a display device.

[0040] [Figure 15] is a cross-sectional view showing an example of a method for manufacturing a transistor.

[0041] [ Figure 16 [ ] is a cross-sectional view showing an example of a display device.

[0042] [Figure 17] is a cross-sectional view showing an example of a method for manufacturing a transistor.

[0043] [ Figure 18 [ ] is a cross-sectional view showing an example of a display device.

[0044] [ Figure 19 [ ] is a cross-sectional view showing an example of a display device.

[0045] [ Figure 20 [ ] is a cross-sectional view showing an example of a display device.

[0046] [ Figure 21 [ ] is a cross-sectional view showing an example of a display device.

[0047] [ Figure 22[ ] is a cross-sectional view showing an example of a display device.

[0048] [Figure 23] is a perspective view showing an example of a display device.

[0049] [ Figure 24 [ ] is a cross-sectional view showing an example of a display device.

[0050] [Figure 25] is a perspective view showing an example of a display device.

[0051] [Figure 26] is a cross-sectional view showing an example of a display device.

[0052] [Figure 27] is a circuit diagram showing an example of a pixel circuit and an example of an operating mode.

[0053] [Figure 28] is a block diagram and timing diagram of the touch sensor.

[0054] [Figure 29] is a block diagram and timing diagram of the display device.

[0055] [Figure 30] is a diagram illustrating the operation of the display device and the touch sensor.

[0056] [Figure 31] is a diagram illustrating the operation of the display device and the touch sensor.

[0057] [Figure 32] is a diagram showing an example of an electronic device.

[0058] [Figure 33] is a diagram showing an example of an electronic device.

[0059] [ Figure 34 [1] is a graph showing the reliability test results of Example 1.

[0060] [ Figure 35 [1] is a graph showing the Id-Vg characteristic measurement results of Example 2.

[0061] [ Figure 36 [Figure 1] shows the GBT stress test results of Example 2.

[0062] [ Figure 37 [Figure 1] shows the results of the constant current stress test in Example 2.

[0063] [ Figure 38 [1] is a graph showing the Id-Vd characteristic measurement results of Example 3.

[0064] Methods of implementing the invention

[0065] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below.

[0066] Note that in the invention structure described below, the same reference numerals are used in different figures to indicate the same parts or parts with the same function, and repeated descriptions are omitted. Additionally, when indicating parts with the same function, the same shading lines are sometimes used without additional reference numerals.

[0067] Furthermore, for ease of understanding, the positions, sizes, and extents of the components shown in the accompanying drawings may not represent their actual positions, sizes, and extents. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and extents disclosed in the accompanying drawings.

[0068] Furthermore, depending on the situation or state, the "film" and "layer" can be interchanged. For example, sometimes a "conductive layer" can be changed into a "conductive film." In addition, sometimes an "insulating film" can be changed into an "insulating layer."

[0069] In this specification and other materials, "metal oxide" refers to oxides of metals in a broad sense. Metal oxides are classified as oxide insulators, oxide conductors (including transparent oxide conductors), and oxide semiconductors (also abbreviated as OS). For example, when a metal oxide is used as the semiconductor layer of a transistor, the metal oxide is sometimes referred to as an oxide semiconductor. In other words, an OS FET can be referred to as a transistor that contains metal oxides or oxide semiconductors.

[0070] In this specification and other materials, nitrogen-containing metal oxides are sometimes referred to as metal oxides. Alternatively, nitrogen-containing metal oxides may also be referred to as metal oxynitrides.

[0071] (Implementation Method 1)

[0072] In this embodiment, a display device according to one aspect of the present invention will be described with reference to FIGS. 1 to 25.

[0073] <Example 1 of the structure of a display device>

[0074] First, the display device of this embodiment will be described with reference to Figures 1 and 2.

[0075] The display device of this embodiment includes a display section and a driving circuit section. The display section includes a liquid crystal element and a first transistor. The driving circuit section includes a second transistor. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The structure of the first transistor is different from that of the second transistor. The first transistor is electrically connected to the pixel electrode. The first transistor has a first region. The pixel electrode, the common electrode, and the first region have the function of transmitting visible light. Visible light passes through the first region and the liquid crystal element and is emitted to the outside of the display device. The first region of the transistor may, for example, be the region connected to the pixel electrode.

[0076] In the display device of this embodiment, the first transistor has a region that transmits visible light. For example, since the contact portion between the first transistor and the pixel electrode transmits visible light, this contact portion can be provided in the display area. This increases the aperture ratio of the pixel, thereby improving light extraction efficiency. Furthermore, since the light extraction efficiency in the pixel can be improved, the brightness of the backlight unit can be reduced. This reduces the power consumption of the display device. Additionally, high-definition display can be achieved.

[0077] In the display device of this embodiment, the structure of the transistors in the display section differs from the structure of the transistors in the driving circuit section. Therefore, the display section and the driving circuit section can each employ transistors with suitable structures. Furthermore, a portion of the manufacturing process for the transistors in the driving circuit section can be shared with a portion of the manufacturing process for the transistors in the display section. This suppresses the increase in the number of manufacturing steps in the display device. Moreover, it suppresses the decrease in yield caused by the increase in steps. For example, in the manufacturing method of the display device of this embodiment, the gate electrodes of the transistors in the display section and the gate electrodes of the transistors in the driving circuit section can be formed in the same process.

[0078] The display section also includes scan lines and signal lines. Both scan lines and signal lines are electrically connected to the first transistor. Both scan lines and signal lines include a metal layer. By using a metal layer for the scan lines and signal lines, their resistance can be reduced. The transistors and wiring in the drive circuit section also use a metal layer. Preferably, the scan lines and signal lines are formed in the same process as the transistors and wiring in the drive circuit section.

[0079] Furthermore, the scan line preferably has a portion that overlaps with the channel region of the first transistor. Depending on the material used for the channel region of the first transistor, illumination can sometimes cause changes in the transistor's characteristics. When the scan line has a portion that overlaps with the channel region of the first transistor, it is possible to suppress external light or backlight from illuminating the channel region. This improves the reliability of the first transistor.

[0080] Figure 1 shows a cross-sectional view of the display device according to this embodiment.

[0081] Figure 1A The display device 10A shown includes a substrate 11, a substrate 12, a transistor 14, a transistor 16, and a liquid crystal element 15. A backlight unit 13 is provided on one side of the substrate 12 of the display device 10A.

[0082] Transistor 14 is disposed in the display section of display device 10A. Transistor 16 is disposed in the drive circuit section of display device 10A. Transistor 14 and transistor 16 have different parts from each other. The two transistors differ from each other, for example, in the type of semiconductor layer or the shape of the transistor. By disposing of transistors with suitable structures in the display section and the drive circuit section respectively, the performance of the display device can be improved.

[0083] The liquid crystal element 15 includes a pixel electrode 21, a liquid crystal layer 22, and a common electrode 23. The pixel electrode 21 is electrically connected to the transistor 14 through an opening in the insulating layer 26. A conductive layer 25, formed using the same process and material as the pixel electrode 21, is disposed on the insulating layer 26. The conductive layer 25 is electrically connected to the common electrode 23 through a connector 29.

[0084] Light 45a from the backlight unit 13 passes through the substrate 12, insulating layer 26, pixel electrode 21, liquid crystal layer 22, common electrode 23, and substrate 11 and is emitted to the outside of the display device 10A. The material of the aforementioned layers that transmit light 45a is a material that transmits visible light.

[0085] Light 45b from the backlight unit 13 passes through the substrate 12, transistor 14, insulating layer 26, pixel electrode 21, liquid crystal layer 22, common electrode 23, and substrate 11 and exits to the outside of the display device 10A. In the display device 10A, the transistor 14, electrically connected to the liquid crystal element 15, includes a region that transmits visible light. Therefore, the region where the transistor 14 is located can also be used as a display area. This increases the pixel aperture ratio. A higher aperture ratio results in higher light extraction efficiency. Therefore, the power consumption of the display device can be reduced. Furthermore, a high-definition display device can be achieved.

[0086] The display device of this embodiment can be used in a display device equipped with a touch sensor (also referred to as an "input / output device" or "touch panel").

[0087] Figure 1B The display device 10B shown has a touch sensor unit 31 disposed on one side of the substrate 11 of the display device 10A.

[0088] Figure 1C The display device 10C shown has a touch sensor unit 31 and an insulating layer 32 disposed between the substrate 11 of the display device 10A and the common electrode 23. The display device 10C also includes a conductive layer 27 and a conductive layer 28.

[0089] A conductive layer 27, formed using the same process and material as the pixel electrode 21, is disposed on the insulating layer 26. A conductive layer 28, formed using the same process and material as the common electrode 23, is disposed in contact with the insulating layer 32. The conductive layer 28 is electrically connected to the touch sensor unit 31. The conductive layer 28 is electrically connected to the conductive layer 27 via a connector 29. Thus, signals for driving the liquid crystal element 15 and signals for driving the touch sensor unit 31 can be provided to the display device 10C via one or more FPCs connected to the substrate 12 side. It is not necessary to connect an FPC or the like to the substrate 11 side, thereby further simplifying the structure of the display device. Compared to the case where FPCs are connected to both the substrate 11 side and the substrate 12 side, it is easier to assemble into electronic devices and the number of components can be reduced.

[0090] In the display device 10C, since the touch sensor unit 31 can be disposed between a pair of substrates, the number of substrates can be reduced, thereby achieving a lighter and thinner display device.

[0091] [pixel]

[0092] Next, the pixels included in the display device of this embodiment will be described with reference to FIG2.

[0093] Figure 2A1 This is a top view of pixel 900. Figure 2A1 The pixel 900 shown includes four sub-pixels. Figure 2A1 This illustrates an example where pixel 900 has two sub-pixels arranged vertically and two sub-pixels arranged horizontally. Each sub-pixel contains a transmissive liquid crystal element 930LC (…). Figure 2A1 (Figure A2 not shown) and transistor 914, etc. In Figure 2A1 In the middle, pixel 900 is provided with two wirings 902 and two wirings 904 respectively. Figure 2A1 The sub-pixels shown represent the display areas of the liquid crystal element (display area 918R, display area 918G, display area 918B and display area 918W).

[0094] Pixel 900 includes wiring 902 and wiring 904, etc. Wiring 902 is used, for example, as a scan line. Wiring 904 is used, for example, as a signal line. Wiring 902 and wiring 904 have portions that intersect each other.

[0095] Transistor 914 is used as a select transistor. The gate of transistor 914 is electrically connected to wiring 902. One of the source and drain of transistor 914 is electrically connected to wiring 904, and the other is electrically connected to liquid crystal element 930LC.

[0096] Here, wiring 902 and wiring 904 are light-shielding. In addition, other layers, that is, the layers that constitute transistor 914, wiring connected to transistor 914, contacts, capacitors, etc., are preferably made of films that are transparent to visible light. Figure 2A2 It is Figure 2A1 The pixel 900 shown is an example of a transmissive region 900t that allows visible light to pass through and a light-blocking region 900s that blocks visible light. Thus, by manufacturing a transistor using a film that is transmissive to visible light, the area other than the wiring 902 and wiring 904 can be called the transmissive region 900t. Since the transmissive region of the liquid crystal element can overlap with the transistor, as well as the wiring, contacts, capacitors, etc., connected to the transistor, the aperture ratio of the pixel can be increased.

[0097] Note that the larger the proportion of the transmissive area in the pixel area, the greater the amount of light transmitted. For example, the proportion of the transmissive area in the pixel area can be set to 1% or more and 95% or less, preferably 10% or more and 90% or less, more preferably 20% or more and 80% or less. Particularly preferred is 40% or more or 50% or more, more preferably 60% or more and 80% or less.

[0098] in addition, Figure 2B Showing is equivalent to along Figure 2A2 The cross-sectional view of the section cut along the dotted line AB is shown. Note that in... Figure 2B The diagram shows cross-sections of components not shown in the top view, such as the liquid crystal element 930LC, color film 932CF, light-shielding film 932BM, and capacitor 915.

[0099] like Figure 2B As shown, light from the backlight unit 13 is emitted in the direction indicated by the dashed arrow. The light from the backlight unit 13 passes through the contact between the transistor 914 and the liquid crystal element 930LC, the transistor 914, and the capacitor 915, and is extracted to the outside. Therefore, the films constituting the transistor 914 and the capacitor 915 preferably have transmittance to visible light. The larger the area of ​​the region of the transistor 914, the capacitor 915, etc., that transmits visible light, the more efficiently the light from the backlight unit 13 can be utilized.

[0100] Note that, as Figure 2B As shown, light from the backlight unit 13 can be extracted to the outside through the color film 932CF. By extracting light through the color film 932CF, the extracted light can be changed to the desired color. The color of the color film 932CF can be selected from red (R), green (G), blue (B), cyan (C), magenta (M), yellow (Y), etc.

[0101] exist Figure 2BIn the process, light from the backlight unit 13 first enters the transistor 914 and capacitor 915, etc. Then, the light passing through the transistor 914 and capacitor 915 enters the liquid crystal element 930LC. Afterward, the light passing through the liquid crystal element 930LC is extracted to the outside through the color film 932CF.

[0102] The transistors, wiring, capacitors, etc. shown in Figure 2 can use the materials shown below. Note that these materials can also be used in the visible light-transmitting semiconductor and conductive layers in the various structural examples shown in this embodiment.

[0103] The semiconductor film included in the transistor can be formed using a semiconductor material that is transparent to visible light. Examples of semiconductor materials that are transparent to visible light include metal oxides or oxide semiconductors. Oxide semiconductors preferably contain at least indium. Particularly preferred are those containing indium and zinc. In addition, it may contain one or more of the following: aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium.

[0104] The conductive film included in the transistor can be formed using a conductive material that is transparent to visible light. Preferably, the conductive material transparent to visible light includes one or more selected from indium, zinc, and tin. Specifically, examples include In oxide, In-Sn oxide (also known as ITO: Indium Tin Oxide), In-Zn oxide, In-W oxide, In-W-Zn oxide, In-Ti oxide, In-Sn-Ti oxide, In-Sn-Si oxide, Zn oxide, Ga-Zn oxide, etc.

[0105] Furthermore, the conductive film included in a transistor can also be formed using an oxide semiconductor that achieves low resistance by containing impurity elements. This oxide semiconductor that achieves low resistance can be called an oxide conductor (OC).

[0106] For example, an oxide conductor is obtained by forming an oxygen defect in an oxide semiconductor and adding hydrogen to the oxygen defect, thereby forming a donor level near the conduction band. Because of the formation of donor levels in the oxide semiconductor, the oxide semiconductor exhibits high conductivity and thus becomes a conductor.

[0107] Note that oxide semiconductors have large band gaps (e.g., band gaps of 2.5 eV or more), and therefore are transparent to visible light. Furthermore, as mentioned above, oxide conductors are oxide semiconductors with donor levels near the conduction band. Therefore, the absorption effect of these donor levels in oxide conductors is relatively small, and they exhibit the same level of transparency to visible light as oxide semiconductors.

[0108] Furthermore, the oxide conductor preferably contains one or more metal elements included in the semiconductor film of the transistor. By using oxide semiconductors containing the same metal element in two or more layers constituting the transistor, manufacturing apparatus (e.g., film deposition apparatus, processing apparatus, etc.) can be used in two or more processes, thus reducing manufacturing costs.

[0109] By employing the pixel structure of the display device shown in this embodiment, light emitted from the backlight unit can be utilized efficiently. This provides an excellent display device with suppressed power consumption.

[0110] <Example 2 of the structure of a display device>

[0111] Next, refer to Figures 3 to 8 The display device of this embodiment will be described.

[0112] First, refer to Figure 3 The display device 100A will be described up to Figure 5.

[0113] Figure 3 This is a perspective view of display device 100A. Figure 3 For clarity, components such as polarizer 130 are omitted. Figure 3 In the middle, the substrate 61 is represented by a dashed line.

[0114] Figure 4 This is a cross-sectional view of display device 100A.

[0115] Figure 5 shows a cross-sectional view illustrating the manufacturing method of transistors 201A and 206A in the display device 100A.

[0116] Figure 3 The display device 100A shown includes a display unit 62 and a driving circuit unit 64. An FPC 72 and an IC 73 are mounted on the display device 100A.

[0117] The display unit 62 includes multiple pixels and has the function of displaying images.

[0118] A pixel comprises multiple subpixels. For example, by using subpixels that display red, subpixels that display green, and subpixels that display blue to form a single pixel, the display unit 62 can perform full-color display. Note that the colors displayed by subpixels are not limited to red, green, and blue. Subpixels that display colors such as white, yellow, magenta, and cyan can also be used within a pixel. In this specification, subpixels are sometimes simply referred to as pixels.

[0119] The display device 100A may include one or both of a scan line driving circuit and a signal line driving circuit, or it may not include both. When the display device 100A includes a sensor such as a touch sensor, it may also include a sensor driving circuit. In this embodiment, an example is shown that includes a scan line driving circuit as a driving circuit unit 64. The scan line driving circuit has the function of outputting scan signals to the scan lines of the display unit 62.

[0120] In the display device 100A, IC73 is mounted on substrate 51 using a mounting method such as COG. IC73 includes, for example, one or more of signal line driving circuits, scan line driving circuits, and sensor driving circuits.

[0121] The FPC72 is electrically connected to the display device 100A. Signals and power are supplied from the outside to the IC73 and the drive circuit section 64 through the FPC72. In addition, signals can be output from the IC73 to the outside through the FPC72.

[0122] Alternatively, ICs can be mounted on the FPC72. For example, one or more ICs, including signal line driver circuits, scan line driver circuits, and sensor driver circuits, can be mounted on the FPC72.

[0123] Signals and power are supplied from wiring 65 to the display unit 62 and the drive circuit unit 64. These signals and power are input to wiring 65 from IC 73 or from the outside via FPC 72.

[0124] Figure 4 This is a cross-sectional view including the display section 62, the driving circuit section 64, and the wiring 65 of the display device 100A. Figure 4 In the subsequent cross-sectional view of the display device, the display unit 62 shows a display area 68 of a sub-pixel and a non-display area 66 located around it.

[0125] Display device 100A is an example of a transmissive liquid crystal display device that uses a liquid crystal element in a horizontal electric field manner.

[0126] like Figure 4As shown, the display device 100A includes a substrate 51, transistors 201A and 206A, a liquid crystal element 40, alignment films 133a and 133b, a connector 204, an adhesive layer 141, a coloring layer 131, a light-shielding layer 132, a protective layer 121, a substrate 61, and a polarizer 130.

[0127] The display device 100A includes a transistor 206A in the display section 62. Additionally, the display device 100A includes a transistor 201A in the drive circuit section 64.

[0128] Transistor 206A includes a visible light transmitting area, which is included within display area 68. Transistor 206A also includes a visible light blocking area, which is included within non-display area 66.

[0129] On the other hand, since transistor 201A is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0130] Transistor 206A includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, a conductive layer 222a, a conductive layer 222b, an insulating layer 225, and a conductive layer 223.

[0131] Transistor 201A includes a conductive layer 291, an insulating layer 211, a semiconductor layer 293, a conductive layer 294a, a conductive layer 294b, an insulating layer 295, and a conductive layer 296.

[0132] Semiconductor layer 231 overlaps with conductive layer 221 through insulating layer 211. Semiconductor layer 231 overlaps with conductive layer 223 through insulating layer 225.

[0133] Semiconductor layer 293 overlaps with conductive layer 291 through insulating layer 211. Semiconductor layer 293 overlaps with conductive layer 296 through insulating layer 295. Semiconductor layer 293 as... Figure 5D The diagram shows a channel region 293a and a pair of low-resistance regions 293b (also referred to as source and drain regions). Note that in this specification and accompanying drawings, the channel region 293a and the low-resistance regions 293b are sometimes collectively referred to as semiconductor layer 293. The channel region 293a is disposed between the pair of low-resistance regions 293b. Additionally, as shown... Figure 4 and Figure 5E As shown, one of the pair of low-resistance regions 293b is electrically connected to the conductive layer 294a, and the other is electrically connected to the conductive layer 294b.

[0134] Semiconductor layers 231 and 293 comprise metal oxides. Semiconductor layer 231 preferably contains indium, and more preferably is an In-M-Zn oxide film (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf). Metal oxides will be described in detail later.

[0135] Conductive layers 222a and 222b are respectively connected to semiconductor layer 231. One of conductive layers 222a and 222b serves as the source and the other as the drain. Conductive layer 222a is electrically connected to signal line 224. Conductive layer 222b is electrically connected to pixel electrode 111.

[0136] Conductive layers 222a and 222b are formed using a conductive material that transmits visible light. This allows the connection between the pixel electrode 111 and the transistor to be positioned in the display area 68. This improves the sub-pixel aperture ratio and reduces the power consumption of the display device.

[0137] Conductive layer 221 and conductive layer 296 are used as gates, respectively. Conductive layer 221 is preferably used as both a gate and a scan line.

[0138] The conductive layer 223 and the conductive layer 291 are used as back gates, respectively.

[0139] One of the conductive layers 294a and 294b is used as the source and the other is used as the drain.

[0140] The conductive materials that transmit visible light and can be used in conductive layers 222a and 222b sometimes have a higher resistivity than conductive materials that block visible light, such as copper or aluminum. To prevent signal delay, buses such as scan lines and signal lines are preferably formed using conductive materials (metallic materials) with low resistivity. However, depending on the pixel size, bus width, bus thickness, etc., the bus can be formed using conductive materials that transmit visible light.

[0141] Specifically, conductive layer 221, conductive layer 291, signal line 224, conductive layer 294a, and conductive layer 294b are preferably formed using conductive materials with low resistivity. These conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, these conductive layers may be formed using conductive materials that block visible light.

[0142] By using a conductive layer that blocks visible light as conductive layer 221 and conductive layer 291, backlight can be suppressed from illuminating the channel regions of semiconductor layer 231 and semiconductor layer 293. Thus, by overlapping the channel formation region of the semiconductor layer with the conductive layer that blocks visible light, light-induced characteristic variations in the transistor can be suppressed. This improves the reliability of the transistor.

[0143] By providing a light-shielding layer 132 on one side of the substrate 61 of the semiconductor layer 231 and a conductive layer 221 that blocks visible light on one side of the substrate 51 of the semiconductor layer 231, the light from external light and backlight can be suppressed from illuminating the channel region.

[0144] In one embodiment of the invention, the conductive layer that blocks visible light may overlap with a portion of the semiconductor layer but not with other portions of the semiconductor layer. For example, the conductive layer that blocks visible light may overlap at least with the channel region.

[0145] Insulating layer 211, insulating layer 225 and insulating layer 295 are used as gate insulating layers respectively.

[0146] Transistor 201A and transistor 206A are transistors with gates located at the top and bottom of the channel, respectively.

[0147] Conductive layers 221 and 223 are preferably electrically connected. Similarly, conductive layers 291 and 296 are preferably electrically connected. Transistors with two electrically connected gates exhibit higher field-effect mobility and increased on-state current compared to other transistors. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the circuit section can be reduced. By using transistors with high on-state current, display devices can be made larger or have higher resolution; therefore, even with an increase in the number of wirings, signal delay in each wiring can be reduced, thereby suppressing display unevenness. Additionally, since the area occupied by the circuit section can be reduced, the display device can have a narrow bezel. Furthermore, this structure enables the implementation of transistors with high reliability.

[0148] The conductive layer 223 and the conductive layer 296 may be a single layer of either a metallic material or an oxide conductor, or a stack of metallic materials and oxide conductors.

[0149] Transistor 206A can be structured as follows: an oxide semiconductor layer is used as semiconductor layer 231, and an oxide conductor (OC) layer (hereinafter also referred to as oxide conductive layer) is used as conductive layer 223. Similarly, transistor 201A can also be structured as follows: an oxide semiconductor layer is used as semiconductor layer 293, and an oxide conductive layer is used as conductive layer 296. In this case, the oxide semiconductor layer and the oxide conductive layer are preferably formed using oxide semiconductors.

[0150] Transistors 201A and 206A are covered by insulating layers 212, 213, and 215. Alternatively, insulating layers 212 and 213 can also be considered as components of the transistor. The transistor is preferably covered by insulating layers that have the effect of suppressing the diffusion of impurities into the semiconductor constituting the transistor. Insulating layer 215 can be used as a planarization layer.

[0151] Insulating layers 211, 225, and 295 preferably all include excess oxygen regions. By having excess oxygen regions in the gate insulating layer, excess oxygen can be supplied to the channel region. Because excess oxygen can fill oxygen defects that may form in the channel region, a highly reliable transistor can be provided.

[0152] The insulating layer 212 preferably contains nitrogen or hydrogen. Nitrogen or hydrogen in the insulating layer 212 can be added to the low-resistance region by contacting the insulating layer 212 with the low-resistance region of the semiconductor layer 293. When nitrogen or hydrogen is added to the low-resistance region, the carrier density increases. Furthermore, when the insulating layer 213 contains nitrogen or hydrogen, the insulating layer 212 allows nitrogen or hydrogen to permeate, thereby allowing nitrogen or hydrogen to be added to the low-resistance region.

[0153] Transistor 201A has a higher field-effect mobility and higher on-state current than transistor 206A. Furthermore, transistor 201A has a smaller parasitic capacitance than transistor 206A. Therefore, it can operate at high speeds even with a smaller transistor size. The area of ​​the drive circuit section 64 can be reduced. Therefore, the area of ​​the non-display area of ​​the display device can be reduced, thereby realizing a display device with a narrow bezel.

[0154] Here, the channel length of transistor 206A refers to the distance between conductive layers 222a and 222b, while the channel length of transistor 201A is the length of conductive layer 296. However, in actual transistor characteristics, the distance between a pair of low-resistance regions of semiconductor layer 293 is the effective channel length of transistor 201A. Sometimes, depending on process conditions, the low-resistance region at the end of conductive layer 296 is not separated from the channel region, and the low-resistance region extends beyond the end of conductive layer 296 towards the channel. In this case, the effective channel length of transistor 201A becomes shorter, resulting in an apparent increase in field-effect mobility. Therefore, it can also be said that transistor 201A has a structure with high field-effect mobility and high on-state current.

[0155] In addition, in transistors 201A and 206A, metal oxide is used as the semiconductor layer.

[0156] Because metal-oxide transistors have low off-state current, the charge stored in the capacitor through the transistor can be maintained for extended periods. By using such transistors in pixels, it is possible to stop the driving circuitry while maintaining the grayscale of the displayed image. As a result, display devices with extremely low power consumption can be realized.

[0157] Furthermore, when the semiconductor layer of a transistor includes metal oxide, the insulation breakdown voltage between the source and drain can be improved. As a result, the reliability of the transistor can be increased.

[0158] The transistor preferably comprises a high-purity metal oxide in which the formation of oxygen defects is suppressed. This reduces the off-state current of the transistor. For example, in a pixel transistor, the hold time of electrical signals such as image signals can be extended, and the write interval can be set to be longer during the power-on state. This reduces the refresh rate, thereby suppressing power consumption.

[0159] In one embodiment of the present invention, the transistors of the display unit 62 and the transistors of the drive circuit unit 64 are formed on the same substrate. Furthermore, the transistors of the drive circuit unit 64 can be transistors capable of high-speed driving. That is, since a separate semiconductor device formed of silicon wafers or the like is not required as the drive circuit, the number of components in the display device can be reduced. In addition, by using high-speed driven transistors in the display unit 62, high-quality images can be provided.

[0160] A liquid crystal element 40 is provided in the display area 68. The liquid crystal element 40 is a liquid crystal element using FFS (Fringe Field Switching) mode.

[0161] The liquid crystal element 40 includes a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. The alignment of the liquid crystal layer 113 can be controlled by generating an electric field between the pixel electrode 111 and the common electrode 112. The liquid crystal layer 113 is located between alignment films 133a and 133b.

[0162] The pixel electrode 111 is electrically connected to the conductive layer 222b.

[0163] The common electrode 112 may have a comb-like top surface shape (also known as a planar shape) or a top surface shape with slits. One or more openings may be formed in the common electrode 112.

[0164] An insulating layer 220 is provided between the pixel electrode 111 and the common electrode 112. The pixel electrode 111 has a portion that overlaps with the common electrode 112 through the insulating layer 220. Furthermore, in the region where the pixel electrode 111 overlaps with the color layer 131, there is a portion on the pixel electrode 111 where the common electrode 112 is not provided.

[0165] Preferably, an alignment film is provided that contacts the liquid crystal layer 113. The alignment film can control the alignment of the liquid crystal layer 113. In the display device 100A, the alignment film 133a is located between the common electrode 112 and the insulating layer 220 and the liquid crystal layer 113, and the alignment film 133b is located between the protective layer 121 and the liquid crystal layer 113.

[0166] As liquid crystal materials, there are positive liquid crystal materials with a positive dielectric anisotropy (Δε) and negative liquid crystal materials with a negative anisotropy. In one aspect of the present invention, any material of either positive or negative type can be used, and a suitable liquid crystal material can be used depending on the mode and design employed.

[0167] Here, an element employing the FFS mode is used as the liquid crystal element 40. However, the present invention is not limited to this, and liquid crystal elements employing various modes can be used. For example, liquid crystal elements employing VA (Vertical Alignment), TN (Twisted Nematic), IPS (In-Plane-Switching), ASM (Axially Symmetric aligned Micro-cell), OCB (Optically Compensated Birefringence), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroelectric Liquid Crystal), ECB (Electrically Controlled Birefringence), VA-IPS (Vertical Alignment In-Plane-Switching), guest-host mode, etc., can be used.

[0168] Alternatively, a normally black liquid crystal display device can be used for the display device 100A, such as a transmissive liquid crystal display device employing vertical alignment (VA) mode. As the vertical alignment mode, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode, ASV (Advanced Super View) mode, etc. can be used.

[0169] Liquid crystal elements (LCDs) are devices that utilize the optical modulation effect of liquid crystals to control the transmission or blocking of light. The optical modulation effect of liquid crystals is controlled by the electric field (horizontal, vertical, or tilted) applied to the liquid crystal. Liquid crystals used in LCD elements can be thermotropic liquid crystals, low-molecular-weight liquid crystals, high-molecular-weight liquid crystals, polymer-dispersed liquid crystals (PDLCs), ferroelectric liquid crystals, antiferroelectric liquid crystals, etc. These liquid crystal materials exhibit cholesteric, smectic, cubic, chiral, and isotropic phases depending on the conditions.

[0170] Furthermore, when using a horizontal electric field, a liquid crystal exhibiting a blue phase can be used without an alignment film. The blue phase is a type of liquid crystal phase that appears just before the cholesteric liquid crystal transitions to a homogeneous phase when the temperature is raised. Because the blue phase only appears within a narrow temperature range, a liquid crystal composition containing at least 5 wt% chiral reagent is used in the liquid crystal layer 113 to broaden the temperature range. Liquid crystal compositions containing both the blue-phase liquid crystal and the chiral reagent have a fast response speed and are optically isotropic. Furthermore, liquid crystal compositions containing both the blue-phase liquid crystal and the chiral reagent do not require alignment processing and have low viewing angle dependence. Additionally, since no alignment film is required and friction processing is unnecessary, electrostatic damage caused by friction processing can be prevented, and defects and breakage of the liquid crystal display device during the manufacturing process can be reduced.

[0171] Because the display device 100A is a transmissive liquid crystal display device, a conductive material that allows visible light to pass through is used for the pixel electrode 111 and the common electrode 112. Furthermore, one or more of the conductive layers included in the transistor 206A use a conductive material that transmits visible light. Therefore, at least a portion of the transistor 206A can be disposed in the display area 68. Figure 4 An example is given when a conductive material that transmits visible light is used for the conductive layer 222b.

[0172] As a conductive material that transmits visible light, materials containing one or more of indium (In), zinc (Zn), and tin (Sn) can be used. Specifically, examples include indium oxide, indium tin oxide (ITO), indium zinc oxide, tungsten-containing indium oxide, tungsten-containing indium zinc oxide, titanium-containing indium oxide, titanium-containing ITO, zinc oxide (ZnO), gallium-containing ZnO, or silicon-containing ITO (ITSO), etc., which are conductive materials that transmit visible light. Alternatively, a film containing graphene can also be used. A film containing graphene can be formed, for example, by reducing a film containing graphene oxide. Alternatively, an oxide conductor (OC) can be used, which is a metal oxide that can be used as a semiconductor layer material with low resistance.

[0173] Preferably, an oxide semiconductor layer is used for one or more of the conductive layer 222b, pixel electrode 111, and common electrode 112. The oxide conductive layer preferably contains one or more metal elements found in the semiconductor layer of the transistor 206A. For example, the conductive layer 222b preferably contains indium, and more preferably is an In-M-Zn oxide film (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn, or Hf). Similarly, the pixel electrode 111 and common electrode 112 preferably both contain indium, and more preferably both are In-M-Zn oxide films.

[0174] Alternatively, oxide semiconductors can be used to form one or more of the conductive layer 222b, pixel electrode 111, and common electrode 112. By using oxide semiconductors containing the same metal element in two or more layers constituting the display device, manufacturing apparatus (e.g., film deposition apparatus, processing apparatus, etc.) can be used in two or more processes, thus reducing manufacturing costs.

[0175] Oxide semiconductors are semiconductor materials whose resistance can be controlled by at least one of oxygen defects and impurity concentrations such as hydrogen and water in the film. Therefore, by selectively treating the oxide semiconductor layer to increase at least one of oxygen defects and impurity concentrations or to decrease at least one of oxygen defects and impurity concentrations, the resistivity of the oxide conductive layer can be controlled.

[0176] Furthermore, the oxide conductive layer formed using the oxide semiconductor layer can also be referred to as an oxide semiconductor layer with high carrier density and low resistance, an oxide semiconductor layer with conductivity, or an oxide semiconductor layer with high conductivity.

[0177] Furthermore, manufacturing costs can be reduced by using the same metal elements to form both the oxide semiconductor layer and the oxide conductive layer. For example, using a metal oxide target composed of the same metal can reduce manufacturing costs. Additionally, using metal oxide targets with the same metal composition allows for the shared use of etching gases or etching solutions during the processing of the oxide semiconductor layer. However, even when the oxide semiconductor layer and the oxide conductive layer have the same metal elements, their compositions can sometimes differ. For example, in the manufacturing process of display devices, metal elements in the film can sometimes detach, resulting in a change in the metal composition.

[0178] For example, when a silicon nitride film containing hydrogen is used for the insulating layer 220 and an oxide semiconductor is used for the pixel electrode 111, the conductivity of the oxide semiconductor can be improved due to the hydrogen supplied from the insulating layer 220.

[0179] A coloring layer 131 and a light-shielding layer 132 are provided on the side of the display device 100A closer to the substrate 61 than the liquid crystal layer 113. The coloring layer 131 is located at least in the portion that overlaps with the display area 68 of the sub-pixel. The light-shielding layer 132 is provided in the non-display area 66 included in the pixel (sub-pixel). The light-shielding layer 132 overlaps at least a portion of the transistor 206A.

[0180] Preferably, a protective layer 121 is provided between the coloring layer 131 and the light-shielding layer 132 and the liquid crystal layer 113. The protective layer 121 can suppress the diffusion of impurities contained in the coloring layer 131 and the light-shielding layer 132 into the liquid crystal layer 113.

[0181] The substrate 51 and the substrate 61 are bonded together using an adhesive layer 141. A liquid crystal layer 113 is sealed in the area surrounded by the substrate 51, the substrate 61 and the adhesive layer 141.

[0182] When the display device 100A is used as a transmissive liquid crystal display device, two polarizers are arranged such that the display unit 62 is sandwiched between them. Figure 4 A polarizer 130 is shown on one side of the substrate 61. Light 45 from a backlight source located outside the polarizer on one side of the substrate 51 enters through the polarizer. At this time, the orientation of the liquid crystal layer 113 can be controlled by the voltage applied between the pixel electrode 111 and the common electrode 112, thereby controlling the optical modulation of the light. That is, the intensity of the light emitted after passing through the polarizer 130 can be controlled. In addition, because light outside the specified wavelength range of the incident light is absorbed by the color layer 131, the emitted light becomes, for example, red, blue, or green light.

[0183] In addition to polarizers, circular polarizers can also be used, for example. A circular polarizer can be made by stacking a linear polarizer and a quarter-wave phase difference plate. Circular polarizers can reduce the viewing angle dependence of the display device.

[0184] Furthermore, the liquid crystal element 40 is preferably driven using a guest-to-subject liquid crystal mode. When using a guest-to-subject liquid crystal mode, a polarizer is not required. This reduces light absorption due to the polarizer, thereby improving light extraction efficiency and resulting in a brighter display.

[0185] In the connection portion 204, the wiring 65 is connected to the conductive layer 251, and the conductive layer 251 is connected to the connector 242. In other words, in the connection portion 204, the wiring 65 is electrically connected to the FPC 72 through the conductive layer 251 and the connector 242. By adopting the above structure, signals and power can be supplied from the FPC 72 to the wiring 65.

[0186] Wiring 65 can be formed using the same material and process as the conductive layers 294a and 294b included in transistor 201A and the signal line 224 included in transistor 206A. Conductive layer 251 can be formed using the same material and process as the pixel electrode 111 included in liquid crystal element 40. Thus, when the conductive layer constituting the connection portion 204 is manufactured using the same material and process as the conductive layer used in the display portion 62 or the driving circuit portion 64, the increase in the number of processes can be suppressed, which is preferable.

[0187] The driving circuit section 64 and the display section 62 may include transistors with multiple structures. For example, it is preferable to use transistors with a structure having two gate electrical connections as one or more of the shift register circuit, buffer circuit, and protection circuit included in the scan line driving circuit.

[0188] [Manufacturing methods for transistors 201A and 206A]

[0189] Next, the manufacturing method of transistors 201A and 206A in the display device 100A will be described with reference to FIG5.

[0190] Thin films (insulating films, semiconductor films, conductive films, etc.) that make up display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). Examples of CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. An example of a thermal CVD method is metal-organic chemical vapor deposition (MOCVD).

[0191] Thin films (insulating films, semiconductor films, conductive films, etc.) that make up display devices can be formed using methods such as spin coating, dip coating, spray coating, inkjet printing, distributor coating, screen printing, offset printing, doctor knife coating, slot coating, roller coating, curtain coating, and doctor knife coating.

[0192] When processing thin films constituting display devices, photolithography and other methods can be used. Additionally, island-shaped thin films can be formed using film deposition methods that utilize masking. Furthermore, thin films can be processed using nanoimprinting, sandblasting, and lift-off methods. Photolithography includes methods such as forming a resist mask on the thin film to be processed, processing the thin film by etching or the like, and then removing the resist mask; and methods that, after forming a photosensitive thin film, expose and develop it to process the film into the desired shape.

[0193] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF lasers, or ArF lasers can also be used. Immersion exposure technology can also be used. Extreme ultraviolet (EUV) light and X-rays can also be used as the light for exposure. Electron beams can also be used instead of the light used for exposure. When using EUV light, X-rays, or electron beams, extremely fine processing can be performed, making them preferred. Furthermore, when exposure is performed by scanning with an electron beam, a photomask is not required.

[0194] As a method for etching thin films, dry etching, wet etching, and sandblasting can be used.

[0195] First, conductive layers 221 and 291 are formed on substrate 51. Next, insulating layers 211 are formed on substrate 51, conductive layers 221, and conductive layers 291. Then, semiconductor layers 231 and 293 are formed on insulating layer 211. Figure 5A ).

[0196] Thus, the conductive layer 291 serving as the back gate of transistor 201A and the conductive layer 221 serving as the gate of transistor 206A can be formed in the same process. Additionally, the insulating layer 211 can serve as both the gate insulating layer of transistor 201A and the gate insulating layer of transistor 206A. Furthermore, the semiconductor layer 293 of transistor 201A and the semiconductor layer 231 of transistor 206A can be formed in the same process.

[0197] The substrate 51 has a degree of rigidity that allows for easy transport and is heat-resistant to the temperatures during the manufacturing process. Examples of materials that can be used to manufacture the substrate 51 include glass, quartz, ceramics, sapphire, resin, semiconductors, metals, or alloys. Examples of glass include alkali-free glass, barium borosilicate glass, and aluminoborosilicate glass.

[0198] Preferably, an insulating layer such as a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a silicon oxynitride film is formed on the substrate 51 as a base film. For example, when glass is used as the substrate 51, forming a base film can prevent impurities in the glass from entering the transistor side.

[0199] Conductive layers 221 and 291 can be formed by forming a resist mask after the conductive film is formed, etching the conductive film, and then removing the resist mask. Other conductive layers described below are formed using the same method.

[0200] The conductive layer 221 and conductive layer 291 can be a single-layer or multi-layer structure made of metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum or tungsten or alloys with these elements as the main components.

[0201] As the insulating layer 211, inorganic insulating films such as silicon nitride film, silicon oxynitride film, silicon oxide film, silicon oxynitride film, aluminum oxide film, and aluminum nitride film can be used. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film can also be used. Furthermore, two or more of the above-mentioned insulating films can be laminated.

[0202] When a metal oxide is used as the semiconductor layer, the insulating layer 211 preferably has an oxide insulating layer in contact with the semiconductor layer. This improves the interface characteristics with the semiconductor layer. For example, the insulating layer 211 preferably includes a nitride insulating layer on the conductive layer 221 and the conductive layer 291, and an oxide insulating layer on the nitride insulating layer. Furthermore, when the insulating layer 211 includes an oxide insulating layer that releases oxygen when heated, the oxygen in the insulating layer 211 can be transferred to the semiconductor layer (metal oxide) through heat treatment, which is therefore preferable.

[0203] Semiconductor layer 231 and semiconductor layer 293 can be formed by forming a resist mask after forming a metal oxide film, etching the metal oxide film, and then removing the resist mask.

[0204] The metal oxide film preferably contains indium, and more preferably is an In-M-Zn oxide film (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf).

[0205] The bandgap of the metal oxide is preferably 2 eV or more, more preferably 2.5 eV or more, and even more preferably 3 eV or more. In this way, by using a metal oxide with a wider bandgap, the off-state current of the transistor can be reduced.

[0206] Metal oxide films can be formed by sputtering. In addition, PLD, PECVD, thermal CVD, ALD, and vacuum evaporation methods can also be used.

[0207] Next, conductive layers 222a and 222b are formed in contact with semiconductor layer 231. Figure 5B ).

[0208] Conductive layers 222a and 222b can be made of conductive materials that are transparent to visible light, such as indium oxide, ITO, indium zinc oxide, indium oxide containing tungsten, indium zinc oxide containing tungsten, indium oxide containing titanium, ITO containing titanium, ZnO, ZnO containing gallium, or ITSO. Alternatively, oxide conductors (OC) that have been modified to have low resistance in metal oxides suitable for use as semiconductor layer materials can be used.

[0209] Next, an insulating layer 225 and a conductive layer 223 are formed on the semiconductor layer 231. Simultaneously with this process, an insulating layer 295 and a conductive layer 296 are formed on the semiconductor layer 293. Figure 5C ).

[0210] Thus, the conductive layer 296 used as the gate of transistor 201A and the conductive layer 223 used as the back gate of transistor 206A can be formed in the same process. Furthermore, the insulating layer 295 of transistor 201A and the insulating layer 225 of transistor 206A can be formed in the same process.

[0211] Insulating layer 225, insulating layer 295, conductive layer 223 and conductive layer 296 can be formed by forming an insulating film that becomes insulating layer 225 and insulating layer 295 and a conductive film that becomes conductive layer 223 and conductive layer 296, forming a resist mask, etching the insulating film and the conductive film, and then removing the resist mask.

[0212] Here, the insulating layer 225 and the conductive layer 223 are formed such that the ends of the insulating layer 225 and the conductive layer 223 are located outside the ends of the semiconductor layer 231. In addition, the insulating layer 295 and the conductive layer 296 are formed such that the ends of the insulating layer 295 and the conductive layer 296 are located inside the ends of the semiconductor layer 293 in the channel length direction of the transistor 201A.

[0213] The materials of insulating layer 225 and insulating layer 295 may be the same as those used for insulating layer 211.

[0214] When a metal oxide is used as the semiconductor layer, insulating layers 225 and 295 preferably have an oxide insulating layer in contact with the semiconductor layer. This improves the interface characteristics with the semiconductor layer. For example, insulating layers 225 and 295 preferably include an oxide insulating layer on the semiconductor layer and a nitride insulating layer on the oxide insulating layer. Furthermore, when insulating layers 225 and 295 include an oxide insulating layer that releases oxygen when heated, heat treatment can transfer oxygen from insulating layers 225 and 295 to the semiconductor layer (metal oxide), which is therefore preferable.

[0215] The materials for conductive layers 223 and 296 can be materials suitable for conductive layers 221 and 291 (such as metals) and materials suitable for conductive layers 222a and 222b (such as transparent conductive materials). The aforementioned oxide conductor (OC) is particularly preferred.

[0216] Next, an insulating layer 212 is formed to cover the semiconductor layer 293, insulating layer 295, conductive layer 296, insulating layer 225, and conductive layer 223, and an insulating layer 213 is formed on the insulating layer 212. Then, openings leading to the semiconductor layer 293 (a pair of low-resistance regions 293b) and openings leading to the conductive layer 222a are formed in the insulating layers 212 and 213. Figure 5D ).

[0217] The insulating layer 212 preferably contains hydrogen. The hydrogen in the insulating layer 212 diffuses into the semiconductor layer 293 in contact with the insulating layer 212, thereby reducing the resistance of a portion of the semiconductor layer 293. The semiconductor layer 293 in contact with the insulating layer 212 serves as a low-resistance region 293b, thereby increasing the on-state current of the transistor 201A and improving the field-effect mobility. Additionally, the portion of the semiconductor layer 293 in contact with the insulating layer 295 serves as a channel region 293a. The resistivity of the low-resistance region 293b is lower than that of the channel region 293a.

[0218] The material of insulating layer 213 can be the same as that used for insulating layer 211. Insulating layer 213 preferably comprises an oxide insulating layer. For example, insulating layer 213 can be a laminate of an oxide insulating layer and a nitride insulating layer.

[0219] Next, conductive layers 294a and 294b and signal line 224 are formed in such a way that the openings provided in insulating layers 212 and 213 are filled. Figure 5E Conductive layer 294a is connected to one of a pair of low-resistance regions 293b. Conductive layer 294b is connected to the other of a pair of low-resistance regions 293b. Signal line 224 is electrically connected to conductive layer 222a.

[0220] Transistor 201A and transistor 206A can be formed through the above-described processes. As mentioned above, a portion of the manufacturing process of transistor 201A and a portion of the manufacturing process of transistor 206A can be performed simultaneously. Therefore, the increase in the number of manufacturing processes for the display device can be suppressed.

[0221] [Example of a variation of display device 100A]

[0222] Next, refer to Figure 6 and... Figure 7 A display device using transistors 201A and 206A, different from display device 100A, will be described. This display device differs from display device 100A in the structure of the liquid crystal element 40. Furthermore, refer to... Figure 8 The display device 100B, which differs from the display device 100A in its transistor structure of the display section 62, will be described. Note that the perspective view of these display devices is different from that of the display device 100A. Figure 3 The display device 100A shown is the same. Furthermore, in the structural examples of the display devices described later, descriptions of structures identical to those of the previous display devices are sometimes omitted.

[0223] Figure 6A The display device 140A shown differs from the previously shown display device 100A in the shape of the pixel electrode 111 and the common electrode 112.

[0224] Pixel electrode 111 and common electrode 112 may both have a comb-shaped top surface shape (also known as a planar shape) or a top surface shape with slits.

[0225] exist Figure 6A In the display device 140A shown, the pixel electrode 111 and the common electrode 112 are disposed on the same plane.

[0226] Furthermore, when viewed from the top, the end of the slit of one electrode can be aligned with the end of the slit of the other electrode. Figure 6B The cross-sectional view at this point is shown.

[0227] Furthermore, viewed from the top, the pixel electrode 111 and the common electrode 112 may also have overlapping portions. Figure 6C The cross-sectional view at this point is shown.

[0228] Furthermore, from the top view, the display unit 62 may also have a portion where the pixel electrode 111 and the common electrode 112 are not provided. Figure 6D The cross-sectional view at this point is shown.

[0229] Figure 7 The display device 140B shown is an example of a transmissive liquid crystal display device that uses a liquid crystal element in a vertical electric field manner.

[0230] The liquid crystal element 40 includes a pixel electrode 111, a common electrode 112, and a liquid crystal layer 113. The liquid crystal layer 113 is located between the pixel electrode 111 and the common electrode 112. An alignment film 133a is disposed in contact with the pixel electrode 111. An alignment film 133b is disposed in contact with the common electrode 112.

[0231] Figure 8 The display device 100B shown includes a transistor 206B in the display section 62. Additionally, the display device 100B includes a transistor 201B in the driving circuit section 64.

[0232] Transistor 201B and Transistor 201A ( Figure 4 The display device 100B has the same structure as the display device 100A. That is to say, the display device 100B differs from the display device 100A in the structure of the transistors in the display section 62, but is otherwise the same as the display device 100A.

[0233] Transistor 206B differs from transistor 206A in the structure of the conductive layer used as the gate. Transistor 206A includes a conductive layer 221 formed from the same process and material as conductive layer 291. On the other hand, transistor 206B includes a conductive layer 229 formed from a different process and material than conductive layer 291.

[0234] The conductive layer 229 is formed of a conductive material that transmits visible light. Therefore, both the connection between the pixel electrode 111 and the conductive layer 222b, and the portion where the conductive layer 229 is disposed, can be located in the display area 68. This improves the aperture ratio of the sub-pixels. Furthermore, it reduces the power consumption of the display device. Figure 8 In the display device 100B shown, conductive layers 222a, 222b, semiconductor layer 231, and conductive layer 229 allow visible light to pass through, while signal line 224 blocks visible light. In transistor 206B, a portion of conductive layer 222a, the connection between conductive layer 222b and pixel electrode 111, semiconductor layer 231, and conductive layer 229 are located in display area 68. In transistor 206B, the connection between conductive layer 222a and signal line 224 is located in non-display area 66.

[0235] When the scan line is located in the non-display area 66, since it is not limited by the transmittance of visible light, a conductive material with low resistivity, such as a metal, can be used to form it. Therefore, it is preferable to provide the conductive layer 229 and the scan line separately. For example, it is preferable to connect the scan line, which is formed in the same process and with the same material as the conductive layer 291, to the conductive layer 229 in the non-display area 66.

[0236] In the manufacturing methods of transistors 201A and 206A described above, transistors 201B and 206B can be manufactured by adding a step to form conductive layer 229 without simultaneously forming conductive layer 221 during the step of forming conductive layer 291. When conductive layer 229 uses a metal oxide, contact with the metal oxide on conductive layer 291 may cause the conductive layer 291 to be oxidized. Therefore, it is preferable to form conductive layer 229 before forming conductive layer 291.

[0237] Figure 8 An example is shown where an opening of a common electrode 112 is formed in the display area 68 of a sub-pixel. As display devices become increasingly high-resolution, the area of ​​the display area 68 of a sub-pixel becomes smaller. Therefore, the number of openings formed in the common electrode 112 is not limited to multiple, but can also be one. That is, in high-resolution display devices, the area of ​​the pixel (sub-pixel) is small, so even if there is only one opening in the common electrode 112, an electric field required for liquid crystal alignment can be generated over the entire display area of ​​the sub-pixel.

[0238] [Material]

[0239] Next, detailed descriptions of the materials, etc., of each component of the display device that can be used in this embodiment will be provided. Note that descriptions of components that have already been described may sometimes be omitted. Furthermore, the following materials may also be appropriately used in the display device, touch panel, and their components shown later.

[0240] There are no particular limitations on the material of the substrate included in the display device according to one aspect of the present invention, and various substrates can be used. For example, glass substrates, quartz substrates, sapphire substrates, semiconductor substrates, ceramic substrates, metal substrates, or plastic substrates can be used.

[0241] By using a thin substrate, display devices can be made lighter and thinner. Furthermore, by using a substrate whose thickness allows for flexibility, flexible display devices can be realized.

[0242] The display device according to one aspect of the present invention includes transistors having either a top-gate or bottom-gate structure. Furthermore, gate electrodes may be disposed above and below the channel. The semiconductor material used for the transistor is not limited thereto; examples include oxide semiconductors, silicon, germanium, etc.

[0243] There are no particular restrictions on the crystallinity of the semiconductor material used in transistors; amorphous semiconductors or crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with a portion of crystalline regions) can be used. When using crystalline semiconductors, the degradation of transistor characteristics can be suppressed, so they are preferred.

[0244] For example, Group 14 elements, compound semiconductors, or oxide semiconductors can be used as semiconductor layers. Typically, semiconductors containing silicon, semiconductors containing gallium arsenide, or oxide semiconductors containing indium can be used as semiconductor layers.

[0245] Oxide semiconductors are preferably used as channeled semiconductors in transistors. In particular, oxide semiconductors with a larger band gap than silicon are preferred. By using a semiconductor material with a wider band gap and lower carrier density than silicon as the semiconductor contained in the semiconductor layer, the off-state current of the transistor can be reduced, which is therefore preferred.

[0246] By using oxide semiconductors, a transistor with suppressed electrical characteristic variations and high reliability can be realized.

[0247] For oxide semiconductors, please refer to the above description and the description of Embodiment 4, etc.

[0248] As insulating materials that can be used in various insulating layers and protective layers included in a display device, both organic and inorganic insulating materials can be used. Examples of organic insulating materials include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyamide-imide resin, siloxane resin, benzocyclobutene resin, and phenolic resin. Examples of inorganic insulating layers include silicon oxide film, silicon oxynitride film, silicon oxynitride film, silicon nitride film, aluminum oxide film, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film.

[0249] Besides the gate, source, and drain of the transistor, the conductive layers, such as wiring and electrodes included in the display device, can be single-layer or multi-layer structures made of metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys with these metals as the main component. Alternatively, conductive materials that are transparent to visible light, such as indium oxide, ITO, indium zinc oxide, indium oxide containing tungsten, indium zinc oxide containing tungsten, indium oxide containing titanium, ITO containing titanium, ZnO, ZnO containing gallium, or ITSO, can be used. Additionally, semiconductors such as polycrystalline silicon or oxide semiconductors, or silicides such as nickel silicides, can be used to reduce resistance by including impurity elements. Furthermore, films containing graphene can also be used. Additionally, semiconductors such as oxide semiconductors containing impurity elements can also be used. Alternatively, conductive pastes such as silver, carbon, or copper, or conductive polymers such as polythiophene can be used. Conductive pastes are inexpensive and therefore preferred. Conductive polymers are easy to apply and therefore preferred.

[0250] Alternatively, an oxide conductive layer can be formed by suppressing the resistivity of the oxide semiconductor.

[0251] As the adhesive layer 141, a thermosetting resin, a light-curing resin, a two-component curing resin, or other curing resin can be used. For example, acrylic resin, polyurethane resin, epoxy resin, or silicone resin can be used.

[0252] As the connector 242, for example, anisotropic conductive film (ACF) or anisotropic conductive paste (ACP) can be used.

[0253] Coloring layer 131 is a colored layer that allows light within a specified wavelength range to pass through. Examples of materials that can be used for coloring layer 131 include metallic materials, resin materials, and resin materials containing pigments or dyes.

[0254] For example, the light-shielding layer 132 is disposed between adjacent coloring layers 131 of different colors. For example, a black matrix formed using a metallic material or a resin material containing pigments or dyes can be used as the light-shielding layer 132. In addition, by disposing the light-shielding layer 132 in an area outside the display section 62, such as the drive circuit section 64, light leakage caused by waveguide light, etc., can be suppressed, which is preferable.

[0255] <Example 3 of the structure of a display device>

[0256] Next, refer to Figure 9 The display device of this embodiment will be described up to Figure 11.

[0257] Figure 9 A cross-sectional view of the display device 100C is shown. Figures 10 and 11 show cross-sectional views illustrating the manufacturing method of transistors 201C and 206C in the display device 100C.

[0258] The display device 100C differs from the display device 100A in the structure of the transistors included in the display section 62 and the driving circuit section 64, but all other structures are the same as those of the display device 100A, so detailed descriptions are omitted.

[0259] The display device 100C includes a transistor 206C in the display section 62. Additionally, the display device 100C includes a transistor 201C in the driving circuit section 64.

[0260] Transistor 206C includes a visible light transmitting area, which is included within display area 68. Transistor 206C also includes a visible light blocking area, which is included within non-display area 66.

[0261] On the other hand, since transistor 201C is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0262] Transistor 206C includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, a conductive layer 222b, and a conductive layer 222c.

[0263] Transistor 201C includes a conductive layer 291, an insulating layer 292, a semiconductor layer 293, a conductive layer 294a, and a conductive layer 294b.

[0264] Transistor 201C and transistor 206C differ in the materials used in their semiconductor layers. Specifically, transistor 201C uses low-temperature polysilicon (LTPS), while transistor 206C uses metal oxide.

[0265] By using LTPS transistors in the drive circuit section 64, the field-effect mobility can be improved compared to using metal oxide transistors, thereby increasing the on-state current. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the drive circuit section 64 can be reduced, thereby enabling narrow bezels in the display device.

[0266] Furthermore, by using metal oxide transistors in the display unit 62, the off-state current can be reduced compared to using LTPS transistors, thus allowing the charge stored in the capacitor through the transistors to be maintained for a longer period. By using such transistors in the display unit 62, the driving circuit can be stopped while maintaining the grayscale of the displayed image. As a result, a display device with extremely low power consumption can be realized.

[0267] The semiconductor layer 231 overlaps with the conductive layer 221 through the insulating layer 211.

[0268] Semiconductor layer 231 contains metal oxide.

[0269] Semiconductor layer 293 overlaps with conductive layer 291 through insulating layer 292. Semiconductor layer 293 as... Figure 10C The diagram shows a channel region 293a and a pair of low-resistance regions 293b. The semiconductor layer 293 may also include an LDD (Lightly Doped Drain) region. Figure 10C An example is shown where an LDD region 293c is included between the channel region 293a and the low-resistance region 293b. Note that in this specification and accompanying drawings, the channel region 293a, the low-resistance region 293b, and the LDD region 293c are sometimes collectively referred to as semiconductor layer 293. A channel region 293a is provided between a pair of low-resistance regions 293b. One of the pair of low-resistance regions 293b is electrically connected to the conductive layer 294a, and the other is electrically connected to the conductive layer 294b. Furthermore, although... Figure 10CThe transistor 201C shown adopts a structure in which the LDD region 293c does not overlap with the conductive layer 291 through the insulating layer 292, but it is also possible to adopt a structure in which the LDD region overlaps with the conductive layer 291 through the insulating layer 292.

[0270] Semiconductor layer 293 includes LTPS.

[0271] Conductive layers 222b and 222c are respectively connected to semiconductor layer 231. One of conductive layers 222b and 222c is used as a source, and the other is used as a drain. Conductive layer 222c is preferably used as a signal line. Conductive layer 222b is electrically connected to pixel electrode 111.

[0272] The conductive layer 222b is formed using a conductive material that transmits visible light. This allows the connection between the pixel electrode 111 and the transistor to be positioned in the display area 68. This improves the aperture ratio of the sub-pixels. Furthermore, it reduces the power consumption of the display device.

[0273] One of the conductive layers 294a and 294b is used as the source and the other is used as the drain.

[0274] Conductive layer 221 and conductive layer 291 are used as gates, respectively. Conductive layer 221 is preferably used as both a gate and a scan line.

[0275] Conductive layers 221, 291, 222c, 294a, and 294b are preferably formed using conductive materials with low resistivity. These conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, these conductive layers may be formed using conductive materials that block visible light.

[0276] In other words, in one embodiment of the present invention, the transistor of the display unit 62 is characterized by having its source electrode and drain electrode formed of different materials. For example, the conductive layer 222b and conductive layer 222c of the transistor 206C are formed of different materials.

[0277] By using a conductive layer that blocks visible light as conductive layer 221, backlight can be suppressed from illuminating the channel region of semiconductor layer 231. Thus, when the channel region overlaps with the light-blocking conductive layer, light-induced characteristic variations in transistor 206C can be suppressed. This improves the reliability of transistor 206C.

[0278] By providing a light-shielding layer 132 on one side of the substrate 61 of the semiconductor layer 231 and a conductive layer 221 that blocks visible light on one side of the substrate 51 of the semiconductor layer 231, the light from external light and backlight can be suppressed from illuminating the channel region.

[0279] Insulating layer 211 and insulating layer 292 are used as gate insulating layers, respectively.

[0280] Transistors 201C and 206C are covered by insulating layers 217, 218, and 215. Alternatively, insulating layers 217 and 218 can also be considered as components of the transistor. The transistor is preferably covered by insulating layers that have the effect of suppressing the diffusion of impurities into the semiconductor constituting the transistor. Insulating layer 215 can be used as a planarization layer.

[0281] Both insulating layers 211 and 217 preferably include excess oxygen regions. By providing excess oxygen regions in the insulating layers that contact the semiconductor layer 231, excess oxygen can be supplied to the channel region. Because excess oxygen can fill oxygen defects that may form in the channel region, a highly reliable transistor can be provided.

[0282] Furthermore, as the insulating layer 217, an oxide insulating film such as a silicon oxide film or a silicon oxynitride film formed in an oxygen-containing atmosphere is preferably used. Moreover, an insulating film such as a silicon nitride film, which does not easily diffuse and permeate, is preferably formed as the insulating layer 218 on the silicon oxide film or silicon oxynitride film. The oxide insulating film formed in an oxygen-containing atmosphere can be an insulating film that easily releases a large amount of oxygen upon heating. By performing heat treatment in a state where this oxygen-releasing oxide insulating film and an insulating film that does not easily diffuse and permeate are stacked together, oxygen can be supplied to the semiconductor layer 231. As a result, oxygen defects in the semiconductor layer 231 and defects at the interface between the semiconductor layer 231 and the insulating layer 217 can be filled, thereby reducing the defect energy level. Thus, a display device with extremely high reliability can be realized.

[0283] Furthermore, the insulating layer 292 is preferably formed using an insulating film containing hydrogen. This allows hydrogen to be supplied from the hydrogen-containing insulating layer 292 to the semiconductor layer 293 to terminate defects in the semiconductor layer 293.

[0284] [Manufacturing methods for transistors 201C and 206C]

[0285] Next, the manufacturing methods of transistors 201C and 206C in the display device 100C will be described with reference to Figures 10 and 11. Furthermore, in the transistor manufacturing methods described later, the descriptions of processes and materials that are the same as those in the preceding transistor manufacturing methods may sometimes be omitted.

[0286] First, a base layer 216 is formed on the substrate 51. Figure 10A ).

[0287] Next, a semiconductor film is formed on the substrate layer 216 using methods such as sputtering or CVD. In this embodiment, an amorphous silicon film is formed using a plasma CVD apparatus.

[0288] Next, the amorphous silicon film is preferably subjected to a heat treatment. This allows hydrogen to be removed from the amorphous silicon film. Specifically, heating is preferably performed at a temperature of 400°C or higher and 550°C or lower. For example, by reducing the hydrogen content in the amorphous silicon film to 5 atom% or less, the manufacturing yield in the crystallization process can be improved. This heat treatment can also be omitted when the hydrogen content in the amorphous silicon film is low.

[0289] Next, by crystallizing the semiconductor film, a semiconductor layer 293 with a crystalline structure is formed. Figure 10A ).

[0290] By irradiating a semiconductor film with a laser from above, the semiconductor film can be crystallized (see reference). Figure 10A (The arrow). As a laser, wavelengths of 193 nm, 248 nm, 308 nm, or 351 nm can be used, for example. Alternatively, a metallic catalyst element (such as nickel) can be used to crystallize the semiconductor film.

[0291] Forming a semiconductor film on a flat surface makes it easier to uniformly irradiate with laser light, which is therefore preferred. For this purpose, it is preferable to form the semiconductor layer 293 before forming other semiconductor and conductive layers. Therefore, transistors employing LTPS preferably have a portion (semiconductor film, etc.) formed first compared to transistors employing metal oxides or amorphous silicon.

[0292] Next, channel doping can be performed on the semiconductor layer 293, which has a crystalline structure.

[0293] Next, the semiconductor layer 293 with a crystalline structure is processed to form an island-shaped semiconductor layer 293. Figure 10B ).

[0294] As a method for processing semiconductor films, either or both of wet etching and dry etching methods can be used.

[0295] Next, an insulating layer 292 is formed on the substrate layer 216 and the semiconductor layer 293. Figure 10C Insulating layer 292 may use materials that can be used in insulating layer 211.

[0296] Then, a conductive layer 221 and a conductive layer 291 ( are formed on the insulating layer 292) are formed on the insulating layer 292. Figure 10C ).

[0297] Thus, the conductive layer 291 used as the gate of transistor 201C and the conductive layer 221 used as the gate of transistor 206C can be formed by the same process.

[0298] Next, a channel region 293a and a low-resistance region 293b are formed by adding impurity elements to a portion of the semiconductor layer 293. Alternatively, an LDD region 293c can be formed between the channel region 293a and the low-resistance region 293b by adding impurity elements multiple times (light doping and heavy doping). The conductive layer 291 and the mask used to manufacture the conductive layer 291 can be used as a mask when adding impurity elements.

[0299] In the fabrication of n-channel transistors, impurities that impart n-type conductivity to the semiconductor layer 293 are used as impurity elements. For example, elements such as P, As, Sb, S, Te, and Se can be used.

[0300] When manufacturing p-channel transistors, impurities that impart p-type conductivity to semiconductor layer 293 are used as impurity elements. For example, elements such as B, Al, and Ga can be used.

[0301] Next, an insulating layer 211 is formed on the insulating layer 292, the conductive layer 221, and the conductive layer 291. Figure 10D ).

[0302] Next, a heat treatment is performed. This activates the impurities added to the semiconductor layer 293. To prevent oxidation of the conductive layers 291 and 221, this heat treatment is preferably performed after the insulating layer 211 is formed.

[0303] Additionally, when insulating layer 292 or insulating layer 211 is a hydrogen-containing insulating layer, hydrogen can be supplied from the hydrogen-containing insulating layer to the semiconductor layer 293 (especially the channel region 293a) by heating to terminate defects in the semiconductor layer 293 with hydrogen. This heat treatment is performed at a temperature lower than that of the heat treatment performed on the amorphous silicon film to remove hydrogen.

[0304] Next, a semiconductor layer 231 is formed on the insulating layer 211. Figure 11A The method for forming semiconductor layer 231 can be found in the description of the manufacturing method of transistor 206A.

[0305] Next, openings are formed in insulating layers 211 and 292 to reach semiconductor layer 293 (a pair of low-resistance regions 293b).

[0306] Next, a conductive layer 222b is formed in contact with the semiconductor layer 231. Additionally, a conductive layer 222c is formed in contact with the semiconductor layer 231. Furthermore, conductive layers 294a and 294b are formed to fill the openings provided in the insulating layers 211 and 292. Figure 11B The conductive layer 294a is connected to one of a pair of low-resistance regions 293b. The conductive layer 294b is connected to the other of a pair of low-resistance regions 293b.

[0307] The conductive layers 294a, 294b and 222c can be formed using the same process and the same material.

[0308] When conductive layer 222b is made of a metal oxide, if the metal oxide is on and in contact with conductive layers 294a, 294b, and 222c, it may cause conductive layers 294a, 294b, and 222c to be oxidized. Therefore, it is preferable to form conductive layer 222b before forming conductive layers 294a, 294b, and 222c.

[0309] Alternatively, the conductive layer 222b can be formed before openings are provided in the insulating layer 211 and the insulating layer 292.

[0310] Next, an insulating layer 217 is formed in such a manner that it covers semiconductor layer 231, insulating layer 211, conductive layer 294a, conductive layer 294b, conductive layer 222b, and conductive layer 222c, and an insulating layer 218 is formed on the insulating layer 217. Figure 11C ).

[0311] As described above, insulating layer 217 is preferably made of an oxide insulating film, and insulating layer 218 is preferably made of a nitride insulating film. For example, materials suitable for insulating layer 211 can be used as materials for the aforementioned insulating films.

[0312] Transistor 201C and transistor 206C can be formed through the above-described processes. As mentioned above, a portion of the manufacturing process of transistor 201C and a portion of the manufacturing process of transistor 206C can be performed simultaneously. Therefore, the increase in the number of manufacturing processes for the display device can be suppressed.

[0313] <Example 4 of the structure of a display device>

[0314] Next, refer to Figure 12 The display device of this embodiment will be described in conjunction with Figure 13.

[0315] Figure 12 A cross-sectional view of the display device 100D is shown. Figure 13 shows a cross-sectional view illustrating the manufacturing method of transistors 201D and 206D in the display device 100D.

[0316] The display device 100D differs from the display device 100A in the structure of the transistors included in the display section 62 and the driving circuit section 64, but all other structures are the same as those of the display device 100A, so detailed descriptions are omitted.

[0317] The display device 100D includes a transistor 206D in the display section 62. Additionally, the display device 100D includes a transistor 201D in the driving circuit section 64.

[0318] Transistor 206D includes a visible light transmitting area, which is included within display area 68. Transistor 206D also includes a visible light blocking area, which is included within non-display area 66.

[0319] On the other hand, since transistor 201D is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0320] Transistor 206D includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, a conductive layer 222b, a conductive layer 222c, an insulating layer 225, and a conductive layer 223.

[0321] Transistor 201D has the same structure as transistor 201C, so detailed descriptions are omitted. Note that in transistor 201C, conductive layers 294a and 294b are connected to semiconductor layer 293 through openings in insulating layers 211 and 292. However, in transistor 201D, conductive layers 294a and 294b are connected to semiconductor layer 293 through openings in insulating layers 212 and 213, in addition to insulating layers 211 and 292.

[0322] Transistor 201D and transistor 206D differ in the materials used in their semiconductor layers. Specifically, transistor 201D uses LTPS, while transistor 206D uses metal oxide.

[0323] As described above, by using LTPS transistors in the drive circuit section 64, the field-effect mobility can be improved compared to the case of using metal oxide transistors, thereby increasing the on-state current. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the drive circuit section 64 can be reduced, thereby enabling a narrow bezel design for the display device.

[0324] Furthermore, by using metal oxide transistors in the display unit 62, the off-state current can be reduced compared to using LTPS transistors, thus allowing the charge stored in the capacitor through the transistors to be maintained for a longer period. By using such transistors in the display unit 62, the driving circuit can be stopped while maintaining the grayscale of the displayed image. As a result, a display device with extremely low power consumption can be realized.

[0325] Semiconductor layer 231 overlaps with conductive layer 221 through insulating layer 211. Semiconductor layer 231 overlaps with conductive layer 223 through insulating layer 225. Semiconductor layer 231 as... Figure 13CThe diagram shows a channel region 231a and a pair of low-resistance regions 231b (also referred to as source and drain regions). Note that in this specification and accompanying drawings, the channel region 231a and the low-resistance regions 231b are sometimes collectively referred to as semiconductor layer 231. The channel region 231a is disposed between the pair of low-resistance regions 231b. Additionally, as shown... Figure 12 and Figure 13C As shown, one of the pair of low-resistance regions 231b is electrically connected to the conductive layer 222c, and the other is electrically connected to the conductive layer 222b.

[0326] Semiconductor layer 231 includes metal oxide.

[0327] One of conductive layers 222b and 222c is used as the source, and the other is used as the drain. Conductive layer 222c is preferably used as a signal line. Conductive layer 222b is electrically connected to pixel electrode 111. Conductive layers 222b and 222c of transistor 206D are formed using different materials.

[0328] The conductive layer 222b is formed using a conductive material that transmits visible light. This allows the connection between the pixel electrode 111 and the transistor to be positioned in the display area 68. This improves the sub-pixel aperture ratio and reduces the power consumption of the display device.

[0329] Conductive layer 223 serves as the gate. Conductive layer 221 serves as the back gate. Conductive layer 221 is preferably formed using the same process and material as the scan lines.

[0330] Conductive layers 221 and 222c are preferably formed using conductive materials with low resistivity. The conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, the conductive layers may be formed using conductive materials that block visible light.

[0331] By using a conductive layer that blocks visible light as conductive layer 221, backlight can be suppressed from illuminating the channel region of semiconductor layer 231. Thus, by overlapping the channel region with the conductive layer that blocks visible light, light-induced characteristic variations in transistor 206D can be suppressed. This improves the reliability of transistor 206D.

[0332] By providing a light-shielding layer 132 on the substrate 61 side of the semiconductor layer 231 and a conductive layer 223 that blocks visible light on the substrate 51 side of the semiconductor layer 231, the light from external light and backlight can be suppressed from illuminating the channel region.

[0333] In one aspect of the invention, the conductive layer that blocks visible light may overlap with a portion of the semiconductor layer but not with other portions of the semiconductor layer. For example, the conductive layer that blocks visible light may overlap at least with the channel region. Specifically, as... Figure 12As shown, the low-resistance region adjacent to the channel region has a region that does not overlap with the conductive layer 221. Furthermore, the low-resistance region can also be referred to as the oxide conductor (OC) described previously. As previously explained, the oxide conductor (OC) is transparent to visible light, so visible light can pass through the low-resistance region for extraction.

[0334] Furthermore, when silicon, such as amorphous silicon or low-temperature polycrystalline silicon, is used as the semiconductor layer of transistor 206D, the region corresponding to the aforementioned low-resistance region can also be referred to as a region containing impurities such as phosphorus and boron in silicon. Additionally, the band gap of silicon is approximately 1.1 eV. Furthermore, the presence of impurities such as phosphorus and boron in silicon can sometimes result in an even lower band gap. Therefore, when silicon is used as the semiconductor layer of transistor 206D, the low-resistance region formed in the silicon has low transmittance of visible light, and light may sometimes be difficult to pass through and thus be extracted. However, in one aspect of the present invention, both oxide semiconductor (OS) and oxide conductor (OC) are transparent to visible light, thus increasing the aperture ratio of the pixel or sub-pixel.

[0335] Insulating layer 211, insulating layer 225 and insulating layer 292 are used as gate insulating layers respectively.

[0336] Transistors 201D and 206D are covered by insulating layers 212, 213, and 215. These layers can be referred to in the description of display device 100A.

[0337] [Manufacturing methods for transistors 201D and 206D]

[0338] Next, the manufacturing method of transistors 201D and 206D in the display device 100D will be described with reference to FIG13.

[0339] First, the manufacturing methods of transistors 201C and 206C ( Figures 10A to 11A Similarly, a base layer 216, an island semiconductor layer 293, an insulating layer 292, a conductive layer 221, a conductive layer 291, an insulating layer 211, and a semiconductor layer 231 are formed on the substrate 51. Figure 13A ).

[0340] In other words, in the manufacturing process of transistor 201D and transistor 206D, conductive layer 291, which serves as the gate of transistor 201D, and conductive layer 221, which serves as the gate of transistor 206D, can be formed in the same process.

[0341] Next, an insulating layer 225 and a conductive layer 223 are formed on the semiconductor layer 231. Figure 13B The subsequent processes can refer to the manufacturing methods of transistors 201A and 206A.

[0342] Here, the insulating layer 225 and the conductive layer 223 are formed such that the ends of the insulating layer 225 and the conductive layer 223 are located inside the ends of the semiconductor layer 231 in the channel length direction of the transistor 206D.

[0343] Next, an insulating layer 212 is formed to cover the insulating layer 211, the semiconductor layer 231, the insulating layer 225, and the conductive layer 223, and an insulating layer 213 is formed on the insulating layer 212. Then, openings leading to the semiconductor layer 293 (a pair of low-resistance regions 293b) and openings leading to the semiconductor layer 231 (a pair of low-resistance regions 231b) are formed in the insulating layer 212 and the insulating layer 213.

[0344] Next, conductive layers 294a, 294b, 222b, and 222c are formed in such a way that the openings provided in insulating layers 212 and 213 are filled. Figure 13C Conductive layer 294a is connected to one of a pair of low-resistance regions 293b. Conductive layer 294b is connected to the other of a pair of low-resistance regions 293b. Conductive layer 222b is connected to one of a pair of low-resistance regions 231b. Conductive layer 222c is connected to the other of a pair of low-resistance regions 231b.

[0345] The conductive layers 294a, 294b and 222c can be formed using the same process and the same material.

[0346] When conductive layer 222b is made of a metal oxide, if the metal oxide is on and in contact with conductive layers 294a, 294b, and 222c, it may cause conductive layers 294a, 294b, and 222c to be oxidized. Therefore, it is preferable to form conductive layer 222b before forming conductive layers 294a, 294b, and 222c.

[0347] Alternatively, the conductive layer 222b can be formed before openings are provided in the insulating layer 212 and the insulating layer 213.

[0348] Transistor 201D and transistor 206D can be formed through the above-described processes. As mentioned above, a portion of the manufacturing process of transistor 201D and a portion of the manufacturing process of transistor 206D can be performed simultaneously. Therefore, the increase in the number of manufacturing processes for the display device can be suppressed.

[0349] <Example 5 of the structure of a display device>

[0350] Next, refer to Figure 14 The display device of this embodiment will be described in conjunction with Figure 15.

[0351] Figure 14A cross-sectional view of the display device 100E is shown. Figure 15 shows a cross-sectional view illustrating the manufacturing method of transistors 201E and 206E included in the display device 100E.

[0352] The display device 100E differs from the display device 100A in the structure of the transistors included in the display section 62 and the driving circuit section 64, but all other structures are the same as those of the display device 100A, so detailed descriptions are omitted.

[0353] The display device 100E includes a transistor 206E in the display section 62. Additionally, the display device 100E includes a transistor 201E in the drive circuit section 64.

[0354] Transistor 206E includes a visible light transmitting area, which is included within display area 68. Transistor 206E also includes a visible light blocking area, which is included within non-display area 66.

[0355] On the other hand, since transistor 201E is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0356] Transistor 206E includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, an auxiliary semiconductor layer 232, a conductive layer 222a, and a conductive layer 222b.

[0357] Transistor 201E includes a conductive layer 291, an insulating layer 292, a semiconductor layer 293, a conductive layer 294a, and a conductive layer 294b.

[0358] The semiconductor layers of transistors 201E and 206E use materials with different crystal structures. Specifically, transistor 201E uses LTPS, while transistor 206E uses amorphous silicon.

[0359] By using LTPS transistors in the drive circuit section 64, the field-effect mobility can be improved compared to using amorphous silicon, thereby increasing the on-state current. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the drive circuit section 64 can be reduced, thereby enabling narrow bezels in the display device.

[0360] Furthermore, when the transistors in the display section 62 are made of amorphous silicon, a laser crystallization process for the display section 62 is not required. Therefore, only the driving circuit section 64 needs to be irradiated with laser, instead of irradiating the entire surface of the substrate. In other words, the area requiring laser crystallization can be reduced.

[0361] When irradiating the entire surface of a substrate with a laser, a linear laser beam is preferred; however, the laser device used to irradiate a linear laser beam is expensive and requires high maintenance. Compared to irradiating the entire surface of the substrate with a laser, irradiating only the drive circuit section 64 with a laser can significantly reduce costs. Furthermore, it is easier to use on large substrates.

[0362] The semiconductor layer 231 overlaps with the conductive layer 221 through the insulating layer 211.

[0363] Semiconductor layer 231 contains amorphous silicon.

[0364] Semiconductor layer 293 overlaps with conductive layer 291 through insulating layer 292. Semiconductor layer 293 has a channel region between a pair of low-resistance regions. One of the pair of low-resistance regions is electrically connected to conductive layer 294a, and the other is electrically connected to conductive layer 294b.

[0365] Semiconductor layer 293 includes LTPS.

[0366] Conductive layers 222a and 222b are electrically connected to semiconductor layer 231, separated by impurity semiconductor layer 232. One of conductive layers 222a and 222b serves as the source, and the other as the drain. Conductive layer 222a is electrically connected to signal line 224. Conductive layer 222b is electrically connected to pixel electrode 111.

[0367] Conductive layers 222a and 222b are formed using a conductive material that transmits visible light. This allows the connection between the pixel electrode 111 and the transistor to be positioned in the display area 68. This improves the sub-pixel aperture ratio and reduces the power consumption of the display device.

[0368] One of the conductive layers 294a and 294b is used as the source and the other is used as the drain.

[0369] Conductive layer 221 and conductive layer 291 are used as gates, respectively. Conductive layer 221 is preferably used as both a gate and a scan line.

[0370] Conductive layers 221, 291, signal line 224, 294a, and 294b are preferably formed using conductive materials with low resistivity. These conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, these conductive layers may be formed using conductive materials that block visible light.

[0371] Insulating layer 211 and insulating layer 292 are used as gate insulating layers, respectively.

[0372] Transistors 201E and 206E are covered by insulating layers 212 and 215. These layers can be referred to in the description of display device 100A.

[0373] [Manufacturing methods for transistors 201E and 206E]

[0374] Next, the manufacturing method of transistors 201E and 206E in the display device 100E will be described with reference to FIG15.

[0375] First, the manufacturing methods of transistors 201C and 206C ( Figures 10A to 10D Similarly, a base layer 216, an island-shaped semiconductor layer 293, an insulating layer 292, a conductive layer 221, a conductive layer 291, and an insulating layer 211 are formed on the substrate 51. Figure 15A ).

[0376] In other words, in the manufacturing process of transistor 201E and transistor 206E, conductive layer 291, which serves as the gate of transistor 201E, and conductive layer 221, which serves as the gate of transistor 206E, can be formed in the same process.

[0377] Next, a semiconductor layer 231 and an impurity semiconductor layer 232 are formed on the insulating layer 211. Figure 15B Here, an amorphous silicon film is formed as semiconductor layer 231, and after an amorphous silicon film with added impurity elements imparting a conductivity type is formed as impurity semiconductor layer 232, a photoresist mask is formed, and both layers are etched together. Then, the photoresist mask is removed.

[0378] Next, conductive layers 222a and 222b are formed on the insulating layer 211, the semiconductor layer 231, and the dummy semiconductor layer 232. Figure 15C Here, when etching the conductive film that forms conductive layers 222a and 222b, a portion of the impurity semiconductor layer 232 is etched to expose the semiconductor layer 231.

[0379] Next, an insulating layer 212 is formed to cover the insulating layer 211, the semiconductor layer 231, the conductive layer 222a, and the conductive layer 222b. Then, openings leading to the semiconductor layer 293 (a pair of low-resistance regions 293b) and openings leading to the conductive layer 222a are formed in the insulating layer 212. At this time, openings may also be formed simultaneously in the insulating layers 292 and 211. Alternatively, openings leading to the semiconductor layer 293 may be formed in the insulating layers 292 and 211 beforehand.

[0380] Next, conductive layers 294a and 294b, and signal lines 224 are formed in such a way that the openings provided in the insulating layer 212, etc., are filled. Figure 15DConductive layer 294a is connected to one of a pair of low-resistance regions 293b. Conductive layer 294b is connected to the other of a pair of low-resistance regions 293b. Signal line 224 is connected to conductive layer 222a.

[0381] The conductive layer 294a, conductive layer 294b and signal line 224 can be formed using the same process and the same materials.

[0382] Transistor 201E and transistor 206E can be formed through the above-described processes. As mentioned above, a portion of the manufacturing process of transistor 201E and a portion of the manufacturing process of transistor 206E can be performed simultaneously. Therefore, the increase in the number of manufacturing processes for the display device can be suppressed.

[0383] <Example 6 of the structure of a display device>

[0384] Next, refer to Figure 16 Figure 17 illustrates the display device of this embodiment.

[0385] Figure 16 A cross-sectional view of the display device 100F is shown. Figure 17 shows a cross-sectional view illustrating the manufacturing method of transistors 201F and 206F included in the display device 100F.

[0386] The display device 100F differs from the display device 100A in the structure of the transistors included in the display section 62 and the driving circuit section 64, but all other structures are the same as those of the display device 100A, so detailed descriptions are omitted.

[0387] The display device 100F includes a transistor 206F in the display section 62. Additionally, the display device 100F includes a transistor 201F in the driving circuit section 64.

[0388] Transistor 206F includes a visible light transmitting region, which is included within display area 68. Transistor 206F also includes a visible light blocking region, which is included within non-display area 66.

[0389] On the other hand, since transistor 201F is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0390] Transistor 206F and transistor 206E have the same structure, so detailed descriptions are omitted. Note that the conductive layer 222a of transistor 206E is electrically connected to the signal line 224 through the insulating layer 212, and the conductive layer 222a of transistor 206F is electrically connected to the signal line 224 through the openings in the insulating layers 212 and 213.

[0391] Transistor 201F includes a conductive layer 291, an insulating layer 211, a semiconductor layer 293, a conductive layer 294a, a conductive layer 294b, an insulating layer 295, and a conductive layer 296.

[0392] Transistor 201F and transistor 206F differ in the materials used in their semiconductor layers. Specifically, transistor 201F uses metal oxide, while transistor 206F uses amorphous silicon.

[0393] By using metal oxide transistors in the driving circuit section 64, the field-effect mobility can be improved compared to using amorphous silicon, thereby increasing the on-state current. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the driving circuit section 64 can be reduced, thereby enabling narrow bezels in the display device.

[0394] Semiconductor layer 293 overlaps with conductive layer 291 through insulating layer 211. Semiconductor layer 293 overlaps with conductive layer 296 through insulating layer 295. Semiconductor layer 293 includes a channel region between a pair of low-resistance regions. One of the pair of low-resistance regions is electrically connected to conductive layer 294a, and the other is electrically connected to conductive layer 294b.

[0395] Semiconductor layer 293 includes metal oxide.

[0396] One of the conductive layers 294a and 294b is used as the source and the other is used as the drain.

[0397] Conductive layer 296 is used as the gate. Conductive layer 291 is used as the back gate.

[0398] Conductive layers 291, 294a, and 294b are preferably formed using conductive materials with low resistivity. These conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, these conductive layers may be formed using conductive materials that block visible light.

[0399] Insulating layer 211 and insulating layer 295 are used as gate insulating layers.

[0400] Transistors 201F and 206F are covered by insulating layers 212, 213, and 215. These layers can be referred to in the description of display device 100A.

[0401] [Manufacturing methods for transistors 201F and 206F]

[0402] Next, the manufacturing method of transistors 201F and 206F in the display device 100F will be described with reference to FIG17.

[0403] First, the manufacturing methods of transistors 201A and 206A ( Figure 5A Similarly, conductive layer 221, conductive layer 291, and insulating layer 211 are formed on substrate 51. Figure 17A ).

[0404] In other words, in the manufacturing process of transistor 201F and transistor 206F, conductive layer 291, which serves as the gate of transistor 201F, and conductive layer 221, which serves as the gate of transistor 206F, can be formed in the same process.

[0405] Next, the manufacturing methods of transistors 201E and 206E ( Figure 15B , Figure 15C Similarly, a semiconductor layer 231, an impurity semiconductor layer 232, a conductive layer 222a, and a conductive layer 222b are formed on the insulating layer 211. Figure 17B ).

[0406] Next, the manufacturing methods of transistors 201D and 206D ( Figure 13A Similarly, semiconductor layer 293, insulating layer 295, and conductive layer 296 are formed (B). Figure 17C ).

[0407] Next, insulating layers 212 and 213 are formed by covering insulating layer 211, semiconductor layer 231, conductive layer 222a, conductive layer 222b, semiconductor layer 293, insulating layer 295, and conductive layer 296. Then, openings leading to semiconductor layer 293 (a pair of low-resistance regions 293b) and openings leading to conductive layer 222a are formed in insulating layers 212 and 213.

[0408] Next, conductive layers 294a and 294b and signal line 224 are formed in such a way that the openings provided in insulating layers 212 and 213 are filled. Figure 17D Conductive layer 294a is connected to one of a pair of low-resistance regions 293b. Conductive layer 294b is connected to the other of a pair of low-resistance regions 293b. Signal line 224 is connected to conductive layer 222a.

[0409] The conductive layer 294a, conductive layer 294b and signal line 224 can be formed using the same process and the same materials.

[0410] Transistor 201F and transistor 206F can be formed through the above-described processes. As mentioned above, a portion of the manufacturing process of transistor 201F and a portion of the manufacturing process of transistor 206F can be performed simultaneously. Therefore, the increase in the number of manufacturing processes for the display device can be suppressed.

[0411] <Structure Example 7 of a Display Device>

[0412] Next, refer to Figures 18 to 20The display device of this embodiment will be described. The common feature of the display devices 110A to 110C illustrated below is that the semiconductor layer of the transistor in the drive circuit section 64 comprises metal oxide. When the semiconductor layer of the transistor comprises metal oxide, the insulation withstand voltage between the source and drain can be improved. As a result, the reliability of the transistor in the drive circuit section 64 can be improved.

[0413] Figure 18 A cross-sectional view of the display device 110A is shown. The display device 110A can be described as having a structure in which the transistors of the display section 62 and the driving circuit section 64 in the display device 100D are reversed. Thus, the structure of the display device in this embodiment, where the transistors of the display section 62 and the driving circuit section 64 are reversed, is also a manifestation of the present invention.

[0414] Transistors 202A and 207A in display device 110A can be manufactured using the same method as transistors 201D and 206D (Fig. 13).

[0415] Figure 19 A cross-sectional view of the display device 110B is shown. The display device 110B can be described as having a structure in which the transistors of the display section 62 and the drive circuit section 64 in the display device 100C are interchanged.

[0416] Display device 110B includes transistor 207B in display section 62. Additionally, display device 100C includes transistor 202B in drive circuit section 64.

[0417] Transistor 207B includes a visible light transmitting area, which is included within display area 68. Transistor 207B also includes a visible light blocking area, which is included within non-display area 66.

[0418] On the other hand, since transistor 202B is located in the drive circuit section 64, it is not considered whether it includes the visible light transmission area.

[0419] Transistor 207B includes a conductive layer 221, an insulating layer 233, a semiconductor layer 231, a conductive layer 222b, and a conductive layer 222c. In transistor 207B, the conductive layer 294a or conductive layer 294b in the structure of transistor 201C is replaced with conductive layer 222b.

[0420] Transistor 202B includes a conductive layer 291, an insulating layer 211, a semiconductor layer 293, a conductive layer 294a, a conductive layer 294b, an insulating layer 217, and a conductive layer 296. In transistor 202B, a conductive layer 296 is added to transistor 206C to serve as a back gate.

[0421] The semiconductor layers of transistor 207B and transistor 202B are made of different materials. Specifically, semiconductor layer 293 of transistor 202B uses metal oxide, while semiconductor layer 231 of transistor 207B uses LTPS.

[0422] Conductive layers 222b and 296 can be formed using the same process and the same material. Conductive layers 222b and 296 are preferably disposed between insulating layers 217 and 218. Preferably, conductive layers 222b and 296 are formed as oxide semiconductor films, and insulating layer 218 is formed as a hydrogen-containing insulating film (especially a hydrogen-containing nitride insulating film). Hydrogen in insulating layer 218 diffuses to conductive layers 222b and 296 in contact with insulating layer 218, reducing the resistance of conductive layers 222b and 296. Therefore, conductive layers 222b and 296 can be oxide conductive layers. Oxide conductive layers are conductive layers that transmit visible light. Therefore, the connection between pixel electrode 111 and transistor can be disposed in display area 68. This improves the sub-pixel aperture ratio. Furthermore, it reduces the power consumption of the display device.

[0423] Figure 20 A cross-sectional view of the display device 110C is shown.

[0424] The display device 110C includes a transistor 207C in the display section 62. Additionally, the display device 110C includes a transistor 202C in the driving circuit section 64.

[0425] Transistor 207C includes a conductive layer 221, an insulating layer 211, a semiconductor layer 231, an auxiliary semiconductor layer 232, a conductive layer 222c, and a conductive layer 222d. The conductive layer 222d is electrically connected to the conductive layer 222b, which is transparent to visible light.

[0426] Transistor 202C includes conductive layer 291, insulating layer 211, semiconductor layer 293, conductive layer 294a, conductive layer 294b, insulating layer 217, insulating layer 218 and conductive layer 296.

[0427] Transistor 202C and transistor 207C differ in the materials used in their semiconductor layers. Specifically, transistor 202C uses metal oxide, while transistor 207C uses amorphous silicon.

[0428] By using metal oxide transistors in the driving circuit section 64, the field-effect mobility can be improved compared to using amorphous silicon, thereby increasing the on-state current. As a result, circuits capable of high-speed operation can be manufactured. Furthermore, the area occupied by the driving circuit section 64 can be reduced, thereby enabling narrow bezels in the display device.

[0429] The semiconductor layer 231 overlaps with the conductive layer 221 through the insulating layer 211.

[0430] Semiconductor layer 231 includes amorphous silicon.

[0431] Semiconductor layer 293 overlaps with conductive layer 291 through insulating layer 211. Semiconductor layer 293 overlaps with conductive layer 296 through insulating layers 217 and 218. Semiconductor layer 293 includes a channel region between a pair of low-resistance regions. One of the pair of low-resistance regions is electrically connected to conductive layer 294a, and the other is electrically connected to conductive layer 294b.

[0432] Semiconductor layer 293 includes metal oxide.

[0433] Conductive layers 222c and 222d are electrically connected to semiconductor layer 231 via impurity semiconductor layer 232, respectively. One of conductive layers 222c and 222d serves as a source, and the other as a drain. Conductive layer 222c is preferably used as a signal line. Conductive layer 222d is electrically connected to pixel electrode 111 via conductive layer 222b.

[0434] The conductive layer 222b is formed using a conductive material that transmits visible light. This allows the connection between the pixel electrode 111 and the transistor to be positioned in the display area 68. This improves the sub-pixel aperture ratio and reduces the power consumption of the display device.

[0435] One of the conductive layers 294a and 294b is used as the source and the other is used as the drain.

[0436] Conductive layer 221 and conductive layer 296 are used as gates. Conductive layer 291 is used as a back gate.

[0437] Conductive layers 221, 291, 222c, 222d, 294a, and 294b are preferably formed using conductive materials with low resistivity. These conductive layers are preferably formed using conductive materials with low resistivity, such as metals or alloys. Alternatively, these conductive layers may be formed using conductive materials that block visible light.

[0438] Insulating layers 211, 217 and 218 are used as gate insulating layers.

[0439] The descriptions of insulating layers 217, 218 and 215 in the preceding display device 100C can be referenced.

[0440] <Example 8 of the structure of a display device>

[0441] Figure 21 A cross-sectional view of the display device 120A is shown. Figure 22 A cross-sectional view of the display device 120B is shown.

[0442] Figure 21 The display unit 62 and the driving circuit unit 64 of the display device 120A shown both use LTPS transistors. Specifically, semiconductor layer 293 and semiconductor layer 231 use LTPS.

[0443] The conductive layer 222b in transistor 208A is electrically connected to the pixel electrode 111. The conductive layer 222b is formed using a conductive material that transmits visible light. Therefore, the connection between the conductive layer 222b and the pixel electrode 111 can be located in the display area 68. This improves the sub-pixel aperture ratio. Furthermore, it reduces the power consumption of the display device.

[0444] Figure 22 The display device 120B shown is a structure in which both the display unit 62 and the driving circuit unit 64 use transistors made of amorphous silicon. Specifically, semiconductor layer 293 and semiconductor layer 231 use amorphous silicon.

[0445] The conductive layer 222d in transistor 208B is electrically connected to pixel electrode 111 via conductive layer 222b. Conductive layer 222b is formed using a conductive material that transmits visible light. This allows the connection between conductive layer 222b and pixel electrode to be located in display area 68. This improves the sub-pixel aperture ratio and reduces the power consumption of the display device.

[0446] <Example 9 of the structure of a display device>

[0447] One aspect of the present invention can be used in a display device (also called an input / output device or touch panel) equipped with a touch sensor. The structure of the aforementioned display devices can be used for a touch panel. In this embodiment, the description mainly focuses on... Figure 4 The example shown is a display device 100A equipped with a touch sensor.

[0448] The sensing element (also referred to as a sensor element) included in the touch panel of one embodiment of the present invention is not limited. Various sensors capable of detecting the proximity or contact of a detection object such as a finger or stylus can also be used as sensing elements.

[0449] For example, various methods can be used as sensors, such as electrostatic capacitive, resistive film, surface acoustic wave, infrared, optical, and pressure-sensitive types.

[0450] In this embodiment, a touch panel including an electrostatic capacitive sensing element will be used as an example for explanation.

[0451] As electrostatic capacitive sensors, there are surface-type electrostatic capacitive sensors and projection-type electrostatic capacitive sensors. Furthermore, projection-type electrostatic capacitive sensors include self-capacitance type and mutual-capacitance type. Mutual-capacitance type is preferred because it allows for simultaneous multi-point sensing.

[0452] The touch panel of one aspect of the present invention can adopt various structures such as a structure in which a display device and a sensing element are bonded together, or a structure in which electrodes constituting the sensing element are provided on one or both of a substrate supporting the display element and an opposing substrate.

[0453] Figure 23 and Figure 24 An example of a touch panel is shown. Figure 23A This is a 3D model of the 350A touch panel. Figure 23B It is Figure 23A An unfolded three-dimensional diagram. Furthermore, for clarity, only typical constituent elements are shown. Figure 23B Substrates 61 and 162 are shown in dashed lines, indicating only their outlines. Figure 24 This is a cross-sectional view of the 350A touch panel.

[0454] The touch panel 350A has a structure that integrates separately manufactured display devices and sensing elements.

[0455] The touch panel 350A includes an input device 375 and a display device 370 arranged in an overlapping manner.

[0456] The input device 375 includes a substrate 162, electrodes 127 and 128, a plurality of wirings 137 and a plurality of wirings 138. The FPC72b is electrically connected to the plurality of wirings 137 and the plurality of wirings 138. An IC73b is disposed on the FPC72b.

[0457] The display device 370 includes substrates 51 and 61 arranged opposite to each other. The display device 370 includes a display section 62 and a driving circuit section 64. Wiring 65 and the like are provided on substrate 51. FPC 72a is electrically connected to wiring 65. IC 73a is provided on FPC 72a.

[0458] Signals and power are supplied from wiring 65 to the display unit 62 and the drive circuit unit 64. These signals and power are input to wiring 65 from the outside or from IC 73a via FPC 72a.

[0459] Figure 24 This is a cross-sectional view of the display unit 62, the driving circuit unit 64, the area including FPC72a, and the area including FPC72b.

[0460] Substrate 51 and substrate 61 are bonded together by adhesive layer 141. Substrate 61 and substrate 162 are bonded together by adhesive layer 169. Here, each layer from substrate 51 to substrate 61 corresponds to display device 370. In addition, each layer from substrate 162 to electrode 124 corresponds to input device 375. That is, adhesive layer 169 bonds display device 370 and input device 375 together.

[0461] Figure 24 The structure of the display device 370 shown is similar to Figure 4 The display device shown is the same as 100A, so detailed descriptions are omitted.

[0462] The substrate 51 and the polarizer 165 are bonded together using adhesive layer 167. The polarizer 165 and the backlight 161 are bonded together using adhesive layer 163.

[0463] Examples of backlight sources 161 include direct-lit backlights and edge-lit backlights. When using a direct-lit backlight with LEDs, complex local dimming can be performed, thereby improving contrast, making it preferred. Conversely, when using an edge-lit backlight, the module including the backlight can be formed thinner, making it preferred as well.

[0464] The substrate 162 and the polarizer 166 are bonded together using an adhesive layer 168. The polarizer 166 and the protective substrate 160 are bonded together using an adhesive layer 164. When the touch panel 350A is installed in an electronic device, the protective substrate 160 can also be used as a substrate that is directly contacted by a sensing object such as a finger or a stylus. As the protective substrate 160, a substrate that can be used as substrate 51 and substrate 61, etc., can be used. As the protective substrate 160, it is preferable to have a structure in which a protective layer is formed on the surface of a substrate that can be used as substrate 51 and substrate 61, etc., or it is preferable to use tempered glass, etc. This protective layer can be formed using a ceramic coating. Alternatively, as this protective layer, it can be formed using inorganic insulating materials such as silicon oxide, aluminum oxide, yttrium oxide, yttrium oxide-stabilized zirconium oxide (YSZ).

[0465] A polarizer 166 can be disposed between the input device 375 and the display device 370. Alternatively, it may not be disposed in this case. Figure 24 The protective substrate 160, adhesive layer 164, and adhesive layer 168 are shown. That is, a structure can be adopted in which the substrate 162 is located on the outermost side of the touch panel 350A. As the substrate 162, it is preferable to use a material that can be used for the aforementioned protective substrate 160.

[0466] Electrodes 127 and 128 are disposed on one side of substrate 61 of substrate 162. Electrodes 127 and 128 are formed on the same plane. An insulating layer 125 is disposed to cover electrodes 127 and 128. Electrode 124 is electrically connected to the two electrodes 128 disposed in a manner that clamps electrode 127 through an opening provided in the insulating layer 125.

[0467] The conductive layer (electrodes 127, 128, etc.) that overlaps with the display area 68 in the conductive layer included in the input device 375 uses a material that allows visible light to pass through.

[0468] Wiring 137, obtained by processing the same conductive layer as electrodes 127 and 128, is connected to conductive layer 126, obtained by processing the same conductive layer as electrode 124. Conductive layer 126 is electrically connected to FPC 72b via connector 242b.

[0469] <Example 10 of the structure of a display device>

[0470] Figure 25 shows an example of a touch panel. Figure 25A This is a perspective view of a touch panel 350B according to one embodiment of the present invention. Figure 25B It is Figure 25A A three-dimensional diagram of the unfolded form. Note that, for clarity, only typical constituent elements are shown. Figure 25B In the image, substrate 61 is shown only by dashed lines, indicating its outline.

[0471] The 350B touch panel is an in-cell touch panel with image display and touch sensor functions.

[0472] The touch panel 350B has a structure in which electrodes and the like constituting the sensing element are disposed only on an opposing substrate. By adopting this structure, compared with a structure that bonds a separately manufactured display device and a sensing element, the touch panel can be made thinner or lighter, or the number of components in the touch panel can be reduced.

[0473] exist Figure 25A and Figure 25B In this embodiment, the input device 376 is disposed on the substrate 61. Furthermore, wiring 137 and wiring 138 of the input device 376 are electrically connected to the FPC 72 disposed on the display device 379. Specifically, in the connection portion 63, one of the wiring 137 (or wiring 138) is electrically connected to a conductive layer disposed on one side of the substrate 51 via a connector (conductive particle, etc.).

[0474] By adopting the above structure, the FPC connected to the touch panel 350B can be configured on only one side of the substrate (here, the substrate 51 side). Alternatively, although a structure could be used to provide more than two FPCs to the touch panel 350B, when... Figure 25A and Figure 25B The structure shown, which uses an FPC72 to provide signals to both the display device 379 and the input device 376, simplifies the structure and is therefore preferred.

[0475] In the touch panel 350B, an FPC supplies signals for driving the pixels and signals for driving the sensing elements. This allows the touch panel 350B to be easily installed in electronic devices and reduces the number of components.

[0476] IC73 can have the function of driving input device 376. Alternatively, an IC for driving input device 376 can be separately mounted on FPC72. Alternatively, the IC for driving input device 376 can be mounted on substrate 51.

[0477] <Example 11 of the structure of a display device>

[0478] Figure 26A , Figure 26B Cross-sectional views of an example of a pixel in the display device of this embodiment are shown. Figure 26A , Figure 26B The cross-sectional view can also be called Figure 2B Examples of deformation of the cross-sectional view.

[0479] Figure 26A , Figure 26B This is an example of a transmissive liquid crystal display device. Figure 26A , Figure 26B As shown, light from the backlight unit 13 is emitted in the direction indicated by the dashed arrow.

[0480] exist Figure 26A and Figure 26B In the backlight unit 13, the light is extracted to the outside through the contact between the transistor 914 and the liquid crystal element 930LC, the transistor 914 and the wiring contact 916, etc.

[0481] Figure 26A The gate electrode, semiconductor layer, source electrode, and drain electrode of transistor 914 are shown as an example of being transmissive to visible light. One of the source electrode and the drain electrode is electrically connected to liquid crystal element 930LC, and the other is electrically connected to wiring 904.

[0482] exist Figure 26AIn the wiring contact 916 shown, two conductive layers that are translucent to visible light are connected to each other. Specifically, a first conductive layer formed in the same process and with the same material as the source and drain electrodes, and a second conductive layer formed in the same process and with the same material as the gate electrode, are connected to each other. Furthermore, the second conductive layer is connected to wiring 902. Thus, the first conductive layer, the second conductive layer, and wiring 902 can be electrically connected. Wiring 902 and wiring 904 are preferably formed using a conductive material with low resistivity. Wiring 902 and wiring 904 may also have light-shielding properties.

[0483] Figure 26B The example shown illustrates that the semiconductor layer of transistor 914, and one of its source and drain electrodes, is transmissive to visible light. One of the source and drain electrodes is electrically connected to the liquid crystal element 930LC.

[0484] exist Figure 26B In this configuration, wiring 904 serves as the other of the source and drain electrodes of transistor 914. Additionally, wiring 902 serves as the gate electrode of transistor 914. The wiring is preferably formed using a conductive material with low resistivity. Wiring 902 and wiring 904 may also have light-shielding properties. Figure 26B The transistor 914 shown has a back gate. There are no restrictions on the light transmittance of the back gate.

[0485] exist Figure 26B In the wiring contact 916 shown, two conductive layers that are translucent to visible light are connected to each other. Specifically, a first conductive layer and a second conductive layer formed from the same process and material as one of the source electrode and the drain electrode are connected to each other. In addition, the second conductive layer is connected to the wiring 902. Thus, the first conductive layer, the second conductive layer, and the wiring 902 can be electrically connected.

[0486] The larger the area of ​​the light-transmitting region included in transistor 914, wiring contact 916, etc., the more efficiently the light from backlight unit 13 can be used.

[0487] As described above, the transistors in the display section of the display device of this embodiment have a visible light-transmitting region. This increases the pixel aperture ratio, thereby improving light extraction efficiency. Consequently, the power consumption of the display device can be reduced.

[0488] Furthermore, in this embodiment, the transistors in the display section and the driving circuit section of the display device have different structures. Moreover, in the manufacturing method of this display device, a portion of the manufacturing process for the transistors in the driving circuit section is also used as a portion of the manufacturing process for the transistors in the display section. Therefore, transistors with structures suitable for both the display section and the driving circuit section can be used while minimizing the increase in the number of manufacturing steps in the display device. Thus, the performance of the display device can be improved while reducing manufacturing costs.

[0489] This embodiment can be appropriately combined with other embodiments. Furthermore, in this specification, where multiple structural examples are shown in one embodiment, these structural examples can be appropriately combined.

[0490] (Implementation Method 2)

[0491] In this embodiment, an operating mode of a display device according to one aspect of the present invention will be described with reference to FIG27.

[0492] The following examples illustrate the normal operating mode, which operates at a typical frame rate (typically above 60Hz and below 240Hz), and the idling stop (IDS) drive mode, which operates at a low frame rate.

[0493] IDS drive mode refers to a driving method that stops rewriting image data after the initial image data write operation. By extending the interval between the first and second image data writes, the power consumption required for writing image data during this period can be eliminated. The frame rate in IDS drive mode can be, for example, about 1 / 100 to 1 / 10 of the normal operating mode. Still images have the same video signal between consecutive frames. Therefore, IDS drive mode is particularly effective when displaying still images. By using IDS drive mode to display images, power consumption can be reduced, image flicker can be suppressed, and eye fatigue can be reduced.

[0494] Figures 27A to 27C This is a timing diagram illustrating the image circuitry and its typical and IDS driving modes. Figure 27A The image shows a first display element 501 (here, a reflective liquid crystal element) and a pixel circuit 506 electrically connected to the first display element 501. Figure 27A The pixel circuit 506 shown includes a signal line SL, a gate line GL, a transistor M1 connected to the signal line SL and the gate line GL, and a capacitor Cs connected to the transistor M1. LC .

[0495] Transistor M1 could potentially become a leakage path for data D1. Therefore, the smaller the off-state current of transistor M1, the better. Preferably, transistor M1 is a transistor in which a metal oxide is incorporated into the semiconductor layer forming the channel. When the metal oxide has at least one of amplification, rectification, and switching functions, it can be called a metal oxide semiconductor, or simply an oxide semiconductor, or OS. Below, as a typical example of a transistor, a transistor using an oxide semiconductor in the semiconductor layer forming the channel (also called an "OS transistor") is described. Compared to transistors using polysilicon, the leakage current (off-state current) of an OS transistor in the non-conducting state is extremely small. By employing an OS transistor as transistor M1, the charge supplied to node ND1 can be maintained for a long period.

[0496] exist Figure 27A In the circuit diagram shown, the liquid crystal element LC is the leakage path for data D1. Therefore, for proper IDS driving, it is preferable to set the resistivity of the liquid crystal element LC to 1.0 × 10⁻⁶. 14 Ω·cm or higher.

[0497] For example, In-Ga-Zn oxides and In-Zn oxides can be used in the channel region of the aforementioned OS transistor. The composition of the aforementioned In-Ga-Zn oxides is typically around In:Ga:Zn = 4:2:4.1 [atomic ratio].

[0498] Figure 27B This is a timing diagram showing the waveforms of the signals supplied to the signal line SL and the gate line GL respectively during normal drive mode. In normal drive mode, it operates at a normal frame rate (e.g., 60Hz). Figure 27B The periods T1 to T3 are shown. During each frame period, a scan signal is supplied to the gate line GL to write data D1 from the signal line SL to the node ND1. This operation is performed regardless of whether the same data D1 is written or different data is written during periods T1 to T3.

[0499] on the other hand, Figure 27C This is a timing diagram showing the waveforms of the signals supplied to signal line SL and gate line GL in IDS drive mode. In IDS drive, it operates at a low frame rate (e.g., 1Hz). A frame period is represented by period T1, where period T... W Indicates the period during which data is written, expressed as period T. RET This indicates the data retention period. In IDS-driven mode, during period T... W A scan signal is supplied to gate line GL, and data D1 from signal line SL is written to the pixel during the period T.RET By fixing the gate line GL to a low level voltage, transistor M1 is de-conducted to retain the written data D1 in the pixel. Low frame rates can be, for example, above 0.1Hz and below 60Hz.

[0500] This implementation method can be appropriately combined with other implementation methods.

[0501] (Implementation Method 3)

[0502] In this embodiment, an example of a method for driving a touch sensor will be described with reference to the accompanying drawings.

[0503] <Examples of sensor sensing methods>

[0504] Figure 28A This is a block diagram illustrating the structure of a mutual capacitance touch sensor. Figure 28A The diagram shows a pulse voltage output circuit 551 and a current detection circuit 552. Additionally, in... Figure 28A In the diagram, the electrode 521 to which a pulse voltage is applied and the electrode 522 to which the change in current is sensed are shown by six wirings, X1 to X6 and Y1 to Y6, respectively. Furthermore, in... Figure 28A The diagram shows a capacitor 553 formed by overlapping electrodes 521 and 522. Note that the functions of electrodes 521 and 522 can be interchanged.

[0505] The pulse voltage output circuit 551 is used to sequentially apply pulse voltages to the wiring from X1 to X6. By applying pulse voltages to the wiring from X1 to X6, an electric field is generated between electrodes 521 and 522 that form capacitor 553. By utilizing the change in mutual capacitance of capacitor 553 caused by the electric field generated between the electrodes due to obstruction or other reasons, the proximity or contact of the sensing object can be detected.

[0506] The current detection circuit 552 is used to detect current changes in the Y1 to Y6 wiring based on changes in the mutual capacitance of capacitor 553. In the Y1 to Y6 wiring, if there is no proximity or contact with a sensing object, the detected current value does not change. On the other hand, when the mutual capacitance decreases due to the proximity or contact with a sensing object, a decrease in the current value is detected. Alternatively, the current can be detected using an integrating circuit or the like.

[0507] Alternatively, one or both of the pulse voltage output circuit 551 and the current detection circuit 552 can be formed in... Figure 4The display section 62 and the driving circuit section 64 are formed simultaneously, which simplifies the process and reduces the number of components used to drive the touch panel, making it preferable. Alternatively, one or both of the pulse voltage output circuit 551 and the current detection circuit 552 can be installed in IC73.

[0508] In particular, when crystalline silicon, such as polycrystalline silicon or monocrystalline silicon, is used as the semiconductor layer for forming the channel as a transistor formed on the substrate 51, the circuit driving capability of the pulse voltage output circuit 551 or the current detection circuit 552 is improved, thereby increasing the sensitivity of the touch sensor.

[0509] Figure 28B Show Figure 28A The diagram shows the timing of the input / output waveforms in a mutual capacitance touch sensor. Figure 28B In this process, the detection of sensed objects in each row and column is performed within a single frame. Additionally, in... Figure 28B The diagram illustrates two scenarios: no sensing object detected (not touched) and a sensing object detected (touched). Furthermore, regarding the wiring from Y1 to Y6, the waveforms of the voltage values ​​corresponding to the detected current values ​​are shown.

[0510] Pulse voltages are sequentially applied to wirings X1 to X6, and the waveforms in wirings Y1 to Y6 change according to these pulse voltages. When no sensing object is approaching or making contact, the waveforms of Y1 to Y6 change according to the voltage changes in wirings X1 to X6. On the other hand, when a sensing object approaches or makes contact, the current value decreases, and therefore the waveform of the corresponding voltage value also changes.

[0511] Thus, by detecting changes in mutual capacitance, the proximity or contact of the sensing object can be sensed.

[0512] <Examples of driving methods for display devices>

[0513] Figure 29A This is a block diagram illustrating a structural example of a display device. Figure 29A This shows a display unit including a gate drive circuit (GD, scan line drive circuit), a source drive circuit (SD, signal line drive circuit), and multiple pixels. Note that in Figure 29A In the diagram, corresponding to the gate lines x_1 to x_m (m is a natural number) electrically connected to the gate drive circuit GD, and the source lines y_1 to y_n (n is a natural number) electrically connected to the source drive circuit SD, each pixel is assigned a sign from (1, 1) to (n, m).

[0514] Figure 29B Yes Figure 29AThe diagram shows the timing of signals applied to the gate and source lines in the display device. Figure 29B The diagram shows the cases where the data signal is rewritten and the cases where the data signal is not rewritten during each frame period. Note that in... Figure 29B In this context, periods such as the retrace period are not considered.

[0515] While rewriting the data signal in each frame period, scan signals are applied sequentially to the gate lines x_1 to x_m. During the horizontal scan period 1H when the scan signal is at level H, data signals D are applied to the source lines y_1 to y_n of each column.

[0516] Without rewriting the data signal during each frame period, the application of scan signals to gate lines x_1 to x_m is stopped. Additionally, during the horizontal scan period 1H, the application of data signals to source lines y_1 to y_n of each column is stopped.

[0517] The driving method that does not rewrite the data signal during each frame period is particularly effective when oxide semiconductors are used in the semiconductor layer forming the channel of the transistors in a pixel. Compared to transistors using semiconductors such as silicon, transistors using oxide semiconductors can reduce the off-state current to an extremely low level. Therefore, the data signal written in the previous period can be retained without rewriting the data signal during each frame period; for example, the grayscale of the pixel can be maintained for more than 1 second, preferably more than 5 seconds.

[0518] Furthermore, when using polysilicon or similar semiconductor layers to form the channels of transistors in a pixel, it is preferable to pre-set a large storage capacitance for the pixel. A larger storage capacitance allows the pixel to maintain its grayscale value for a longer period. The size of the storage capacitance can be set according to the leakage current of the transistor or display element electrically connected to the storage capacitance. For example, when the storage capacitance for each pixel is 5 fF or more and 5 pF or less, preferably 10 fF or more and 5 pF or less, and more preferably 20 fF or more and 1 pF or less, the data signal written in previous periods can be retained without rewriting the data signal during each frame period. For example, the pixel's grayscale value can be maintained for several or tens of frames.

[0519] <Examples of driving methods for display units and touch sensors>

[0520] Figures 30A to 30D This is used as an example to illustrate the driver. Figure 28A and Figure 28B The described touch sensor and Figure 29A and Figure 29B The diagram illustrates the operation of the display unit during a continuous frame period of 1 second. Additionally, Figure 30AThe diagram shows a case where the frame duration of the display is set to 16.7 ms (frame rate: 60 Hz), and the frame duration of the touch sensor is also set to 16.7 ms (frame rate: 60 Hz). Figures 30 and 31, 1F, 2F... represent the frames of the display or the touch sensor.

[0521] In one aspect of the display device of the present invention, the operation of the display unit and the touch sensor are independent of each other, and the touch sensing period can be set in parallel with the display period. Therefore, as Figure 30A As shown, the frame period for both the display and the touch sensor can be set to 16.7ms (frame rate: 60Hz). Alternatively, the frame rates for the touch sensor and the display can be different. For example, as... Figure 30B As shown, the frame period of the display can also be set to 8.3ms (frame rate: 120Hz), and the frame period of the touch sensor can be set to 16.7ms (frame rate: 60Hz). Alternatively, although not shown, the frame rate of the display can also be set to 33.3ms (frame rate: 30Hz).

[0522] Furthermore, by setting the frame rate of the display unit to a switchable structure, and increasing the frame rate (e.g., 60Hz or higher or 120Hz or higher) when displaying dynamic images, and decreasing the frame rate (e.g., 60Hz or lower, 30Hz or lower or 1Hz or lower) when displaying static images, the power consumption of the display device can be reduced. Alternatively, the frame rate of the touch sensor can also be set to a switchable structure, and the frame rate during standby can be different from the frame rate when a touch is detected.

[0523] Furthermore, in a display device according to one aspect of the present invention, by maintaining the data signal rewritten in the preceding period without rewriting the data signal in the display section, a frame period of the display section can be set to a period longer than 16.7 ms. Therefore, as Figure 30C As shown, the frame period of the display can be set to 1 sec (frame rate: 1 Hz) and the frame period of the touch sensor can be set to 16.7 ms (frame rate: 60 Hz).

[0524] Furthermore, regarding the structure of the data signal that is retained during the previous period without rewriting the data signal in the display section, the IDS driving mode described above can be referred to. The IDS driving mode can also be a partial IDS driving mode where the data signal is rewritten only in a specific area of ​​the display section. A partial IDS driving mode refers to a mode where the data signal is rewritten only in a specific area of ​​the display section, while the data signal rewritten during the previous period is retained in other areas.

[0525] Furthermore, according to the touch sensor driving method shown in this embodiment, during the... Figure 30CUnder the driving conditions shown, the touch sensor can be driven continuously. Therefore, as... Figure 30D As shown, the data signal of the display unit can also be rewritten when the proximity or contact of the object sensed in the touch sensor is detected.

[0526] If the data signal of the display unit is rewritten during the sensing period of the touch sensor, the noise generated during the data signal rewriting process may be transmitted to the touch sensor, potentially reducing its sensitivity. Therefore, it is preferable to perform the rewriting of the display unit's data signal and the sensing by the touch sensor at different times.

[0527] Figure 31A An example is shown where the data signal rewriting of the display unit and the sensing of the touch sensor are performed alternately. Additionally, Figure 31B This example illustrates a touch sensor sensing operation performed every two data signal rewriting operations on the display unit. Note that this is not a limitation; the touch sensor may also be sensed every three or more rewriting operations.

[0528] Furthermore, when oxide semiconductors are used as the semiconductor layer forming the channel of the transistor in a pixel, the off-state current can be reduced to an extremely low level, thus significantly reducing the frequency of data signal rewriting. Specifically, a sufficiently long stop period can be set between the rewriting of the data signal and the subsequent rewriting. The stop period can be, for example, 0.5 seconds or more, 1 second or more, or 5 seconds or more. The upper limit of the stop period is limited by the leakage current of capacitors or display elements connected to the transistor, and can be, for example, less than 1 minute, less than 10 minutes, less than 1 hour, or less than 1 day.

[0529] Furthermore, when the semiconductor layer in which the channel for the transistor used as a pixel is formed is LTPS or amorphous silicon, a structure can be adopted to store the data signal by setting SRAM at the node holding the pixel's data signal. By adopting this structure, the data signal rewriting frequency can be significantly reduced. Moreover, the data signal rewriting frequency can be set to a rewriting frequency equivalent to that described above when oxide semiconductor is used as the semiconductor layer.

[0530] Figure 31C This illustrates an example of rewriting the display's data signal at a frequency of once every 5 seconds. Figure 31C In the display section, a stop period is provided between the rewriting of the data signal and the next rewriting operation. During the stop period, the touch sensor can be driven at a frame rate of iHz (where i is a frame rate of the display device or higher, in this case 0.2Hz or higher). Alternatively, as... Figure 31CAs shown, by performing 5i-times of touch sensor sensing during the stop period and not performing touch sensor sensing during the data signal rewriting period of the display unit, the sensitivity of the touch sensor can be improved, and therefore it is preferred. Furthermore, as... Figure 31D As shown, by simultaneously rewriting the data signal of the display unit and sensing the touch sensor, the driving signal can be simplified.

[0531] Furthermore, during periods when the data signal rewriting operation of the display unit is not being performed, the supply of data signals to the display unit can be stopped, and the operation of one or both of the gate drive circuit GD and the source drive circuit SD can be stopped. Moreover, the power supply to one or both of the gate drive circuit GD and the source drive circuit SD can also be stopped. This further reduces noise and improves the sensitivity of the touch sensor. Additionally, the power consumption of the display device can be further reduced.

[0532] One embodiment of the present invention provides a display device having a structure in which a display unit and a touch sensor are sandwiched between two substrates. Therefore, the distance between the display unit and the touch sensor can be minimized. However, noise generated during the operation of the display unit can easily be transmitted to the touch sensor, potentially reducing its sensitivity. By using the driving method illustrated in this embodiment, a display device comprising a touch panel that simultaneously achieves thinness and high detection sensitivity can be obtained.

[0533] This implementation method can be appropriately combined with other implementation methods.

[0534] (Implementation Method 4)

[0535] In this embodiment, a metal oxide that can be used in the semiconductor layer of a transistor disclosed in one aspect of the present invention will be described. Note that when a metal oxide is used in the semiconductor layer of a transistor, the metal oxide may also be referred to as an oxide semiconductor.

[0536] Oxide semiconductors are classified into single-crystal oxide semiconductors and non-single-crystal oxide semiconductors. Non-single-crystal oxide semiconductors include CAAC-OS (c-axis-aligned crystalline oxide semiconductor), polycrystalline oxide semiconductors, nc-OS (nanocrystalline oxide semiconductor), a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors, etc.

[0537] The semiconductor layer of the transistor disclosed as one aspect of the present invention can also use CAC-OS (Cloud-Aligned Composite oxide semiconductor).

[0538] The semiconductor layer of the transistor disclosed in one embodiment of the present invention can use the aforementioned non-single-crystal oxide semiconductor or CAC-OS. Furthermore, nc-OS or CAAC-OS is preferred as the non-single-crystal oxide semiconductor.

[0539] In one embodiment of the invention, CAC-OS is preferably used as the semiconductor layer of the transistor. By using CAC-OS, the transistor can be endowed with high electrical characteristics or high reliability.

[0540] The following is a detailed explanation of CAC-OS.

[0541] CAC-OS or CAC-metal oxide possesses conductive properties in one part of the material and insulating properties in another, thus functioning as a semiconductor as a whole. Furthermore, when CAC-OS or CAC-metal oxide is used in the channel formation region of a transistor, the conductive function allows electrons (or holes) used as charge carriers to flow through, while the insulating function prevents electrons from flowing through. Through the complementary effects of conductive and insulating functions, CAC-OS or CAC-metal oxide can possess switching functions (on / off functionality). By separating these functions within CAC-OS or CAC-metal oxide, each function can be maximized.

[0542] Furthermore, CAC-OS or CAC-metal oxide comprises conductive and insulating regions. The conductive regions possess the aforementioned conductive function, and the insulating regions possess the aforementioned insulating function. Moreover, in the material, the conductive and insulating regions are sometimes separated at the nanoparticle level. Additionally, the conductive and insulating regions are sometimes unevenly distributed within the material. Furthermore, sometimes the conductive regions are observed to have blurred edges and be connected in a cloud-like manner.

[0543] In CAC-OS or CAC-metal oxide, conductive and insulating regions are sometimes dispersed in the material with a size of 0.5 nm or more and 10 nm or less, preferably 0.5 nm or more and 3 nm or less.

[0544] Furthermore, CAC-OS or CAC-metal oxide is composed of components with different band gaps. For example, CAC-OS or CAC-metal oxide is composed of a component with a wide gap originating from an insulating region and a component with a narrow gap originating from a conductive region. In this configuration, when charge carriers flow through, they mainly flow in the component with the narrow gap. Moreover, the component with the narrow gap complements the component with the wide gap, and charge carriers flow in the component with the wide gap in conjunction with the component with the narrow gap. Therefore, when the above-mentioned CAC-OS or CAC-metal oxide is used in the channel formation region of a transistor, a high current driving force, i.e., a large on-state current and a high field-effect mobility, can be obtained in the transistor's on-state.

[0545] In other words, CAC-OS or CAC-metal oxide can also be referred to as matrix composite or metal matrix composite.

[0546] CAC-OS, for example, refers to a composition in which elements are unevenly distributed within a metal oxide, wherein the size of the material containing the unevenly distributed elements is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or approximately. Note that below, the state in which one or more metal elements are unevenly distributed within a metal oxide and the regions containing those metal elements are mixed is also referred to as mosaic or patch-like, wherein the size of the region is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or approximately.

[0547] The metal oxide preferably contains at least indium. In particular, it preferably contains both indium and zinc. In addition, it may also contain one or more of the following: aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium.

[0548] For example, CAC-OS in In-Ga-Zn oxides (in particular, In-Ga-Zn oxides can be referred to as CAC-IGZO) refers to materials that are indium oxides (hereinafter referred to as InO). X1 (X1 is a real number greater than 0) or indium zinc oxide (hereinafter referred to as In X2 Zn Y2 O Z2 (X2, Y2, and Z2 are real numbers greater than 0) and gallium oxide (hereinafter referred to as GaO) X3 (X3 is a real number greater than 0) or gallium zinc oxide (hereinafter referred to as Ga X4 ZnY4 O Z4 (X4, Y4, and Z4 are real numbers greater than 0) etc., thus forming a mosaic pattern, and the mosaic-shaped InO X1 or In X2 Zn Y2 O Z2 The composition (hereinafter also referred to as cloud-like) is uniformly distributed in the membrane.

[0549] In other words, CAC-OS is a system with GaO X3 The region with In as the main component and X2 Zn Y2 O Z2 or InO X1 A composite metal oxide consisting of regions that are the main components mixed together. In this specification, for example, when the ratio of the number of In atoms to the number of element M atoms in the first region is greater than that in the second region, the In concentration in the first region is higher than that in the second region.

[0550] Note that IGZO is a general term, sometimes referring to compounds containing In, Ga, Zn, and O. A typical example is InGaO3 (ZnO). m1 (m1 is a natural number) or In （1+x0） Ga （1-x0） O3 (ZnO) m0 (-1≤x0≤1, m0 is any number) represents a crystalline compound.

[0551] The aforementioned crystalline compounds have single-crystal, polycrystalline, or CAAC (c-axis aligned crystal) structures. The CAAC structure is a crystalline structure in which multiple IGZO nanocrystals have c-axis orientation and are connected in a non-oriented manner on the ab plane.

[0552] On the other hand, CAC-OS is related to the material composition of metal oxides. CAC-OS refers to a material composition containing In, Ga, Zn, and O, in one part of which nanoparticle-like regions with Ga as the main component are observed, and in another part, nanoparticle-like regions with In as the main component are observed to be randomly dispersed in a mosaic pattern. Therefore, in CAC-OS, the crystal structure is a secondary factor.

[0553] CAC-OS does not contain stacked structures consisting of two or more different membranes. For example, it does not contain a structure consisting of two layers: one with In as the main component and the other with Ga as the main component.

[0554] Note that sometimes GaO cannot be observed. X3 Regions with In as the main component X2 ZnY2 O Z2 or InO X1 Clear boundaries between regions that are the main components.

[0555] In the case where CAC-OS contains one or more of the elements selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium to replace gallium, CAC-OS refers to a composition in which nanoparticle-like regions with the element as the main component are observed in one part, and nanoparticle-like regions with In as the main component are observed to be randomly dispersed in a mosaic pattern in another part.

[0556] CAC-OS can be formed, for example, by sputtering without intentionally heating the substrate. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gases, and nitrogen gases can be used as the film-forming gas. Furthermore, the lower the proportion of oxygen gas in the total flow rate of the film-forming gas during film formation, the better; for example, the oxygen gas flow rate ratio is set to 0% or more and less than 30%, preferably 0% or more and less than 10%.

[0557] CAC-OS has the following characteristics: when measured using the out-of-plane method (XRD), one of the methods for X-ray diffraction, with θ / 2θ scanning, no clear peak is observed. In other words, based on X-ray diffraction, it can be determined that there is no orientation in the ab plane direction or the c-axis direction within the measurement region.

[0558] Furthermore, in the electron diffraction pattern of CAC-OS obtained by irradiating it with an electron beam with a diameter of 1 nm (also known as a nanobeam), a ring-shaped region of high brightness and multiple bright spots within this ring-shaped region were observed. Therefore, based on the electron diffraction pattern, it can be concluded that the crystal structure of CAC-OS has an nc (nano-crystal) structure that is unoriented in both the planar and cross-sectional directions.

[0559] Furthermore, for example, in CAC-OS of In-Ga-Zn oxides, based on EDX surface analysis images obtained by energy dispersive X-ray spectroscopy (EDX), it can be confirmed that: it has GaO X3 Regions with In as the main component and X2 Zn Y2 O Z2 or InO X1 A mixture of components whose main components are unevenly distributed in different regions.

[0560] CAC-OS differs in structure from IGZO compounds, which have a uniform distribution of metallic elements, and thus exhibits different properties. In other words, CAC-OS possesses properties centered around GaO. X3 Regions with In as the main component and In X2 Zn Y2 O Z2 or InO X1 The regions that are the main components are separated from each other, and the regions that are the main components of each element are mosaic-like.

[0561] Here, in In X2 Zn Y2 O Z2 or InO X1 The conductivity of regions with GaO as the main component is higher than that of regions with GaO as the main component. X3 The region is dominated by components such as In. In other words, when charge carriers flow through a region dominated by In X2 Zn Y2 O Z2 or InO X1 When In is the dominant component, it exhibits the conductivity of an oxide semiconductor. Therefore, when In... X2 Zn Y2 O Z2 or InO X1 When the region that is the main component is distributed in a cloud-like manner in an oxide semiconductor, a high field-effect mobility (μ) can be achieved.

[0562] On the other hand, with GaO X3 The insulation of regions with In as the main component is higher than that of regions with In as the main component. X2 Zn Y2 O Z2 or InO X1 The region where GaO is the main component. In other words, when GaO is used... X3 When regions with these as the main components are distributed in an oxide semiconductor, leakage current can be suppressed, thus achieving good switching operation.

[0563] Therefore, when CAC-OS is used in semiconductor devices, it is due to GaO X3 The insulation properties of In and other materials and their causes X2 Zn Y2 O Z2 or InO X1 The complementary effect of their conductivity can achieve high on-state current (I0). on ) and high field-effect mobility (μ).

[0564] Furthermore, semiconductor components using CAC-OS exhibit high reliability. Therefore, CAC-OS is suitable for various semiconductor devices such as displays.

[0565] This implementation method can be appropriately combined with other implementation methods.

[0566] (Implementation Method 5)

[0567] In this embodiment, an electronic device according to one aspect of the present invention is described.

[0568] Examples of electronic devices include: television sets; desktop or laptop personal computers; monitors for computers, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game consoles; portable information terminals; sound reproduction devices; and large game machines such as pinball machines.

[0569] Figures 32A to 32C A portable information terminal is shown. The portable information terminal of this embodiment has one or more functions selected from telephones, laptops, and information reading devices. Specifically, the portable information terminal of this embodiment can be used as a smartphone or smartwatch. The portable information terminal of this embodiment can, for example, execute various applications such as mobile phone calls, email, article reading and editing, music playback, animation playback, network communication, and computer games. Figures 32A to 32C The portable information terminal shown can have various functions. For example, it can have the following functions: displaying various information (still images, moving images, text images, etc.) on the display; a touch panel; displaying calendars, dates, or times; controlling processing via various software (programs); wireless communication; connecting to various computer networks via wireless communication; sending or receiving various data via wireless communication; reading programs or data stored on recording media and displaying them on the display, etc. Note that... Figures 32A to 32C The portable information terminal shown may have functions other than those described above.

[0570] Figures 32A to 32C The portable information terminal shown can run various applications such as mobile phone, email, article reading and editing, music playback, internet communication, and computer games. In addition, Figures 32A to 32C The portable information terminal shown can perform short-range wireless communication based on communication standards. For example, it can communicate with a headset capable of wireless communication. Figure 32C The wristwatch-style portable information terminal 820 shown can make hands-free calls.

[0571] Figure 32A The portable information terminal 800 shown includes a frame 811, a display unit 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, etc. The display unit 812 of the portable information terminal 800 has a flat surface.

[0572] Figure 32B The portable information terminal 810 shown includes a frame 811, a display unit 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, a camera 817, etc. The display unit 812 of the portable information terminal 810 has a curved surface.

[0573] Figure 33C A watch-type portable information terminal 820 is shown. The portable information terminal 820 includes a frame 811, a display unit 812, a speaker 815, and operation keys 818 (including a power switch or operation switch). The display unit 812 of the portable information terminal 820 is circular in shape. The display unit 812 of the portable information terminal has a flat surface.

[0574] The display device according to one aspect of the present invention can be used in the display unit 812. Therefore, a portable information terminal including a display unit with a high aperture ratio can be manufactured.

[0575] In the portable information terminal of this embodiment, a touch sensor is provided in the display unit 812. Various operations such as making phone calls or inputting text can be performed by touching the display unit 812 with a finger or stylus.

[0576] Additionally, by operating button 813, the power can be switched on / off or the types of images displayed on the display unit 812 can be changed. For example, the email composing screen can be switched to the main menu screen.

[0577] Furthermore, by incorporating a gyroscope sensor or accelerometer sensor within the portable information terminal, the terminal's orientation (vertical or horizontal) can be determined, and the display orientation of the display unit 812 can be automatically switched. Alternatively, the display orientation can be switched by touching the display unit 812, operating the operation button 813, or inputting sound using the microphone 816.

[0578] exist Figure 33A In the television device 7100 shown, a display unit 7102 is assembled in the frame 7101. Images can be displayed by the display unit 7102. A display device according to one aspect of the present invention can be used in the display unit 7102. Thus, a television device including a display unit with a high aperture ratio can be manufactured. The structure in which the frame 7101 is supported by a bracket 7103 is shown here.

[0579] The television device 7100 can be operated using the operation switch provided in the housing 7101 or the separately provided remote control 7111. Using the operation keys provided in the remote control 7111, channels and volume can be adjusted, and the image displayed on the display unit 7102 can be manipulated. Alternatively, a structure can be adopted in which a display unit for displaying information output from the remote control 7111 is provided within the remote control 7111.

[0580] The television device 7100 is equipped with a receiver, modem, and other components. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, one-way (from sender to receiver) or two-way (between sender and receiver or between receivers, etc.) information communication can be performed.

[0581] Figure 33B The computer 7200 shown includes a main body 7201, a frame 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by using a display device according to one aspect of the present invention in its display unit 7203. Therefore, it is possible to manufacture a computer including a display unit with a high aperture ratio.

[0582] Figure 33C The camera 7300 shown includes a frame 7301, a display unit 7302, operation buttons 7303, a shutter button 7304, etc. In addition, the camera 7300 is equipped with a detachable lens 7306.

[0583] The display device according to one aspect of the present invention can be used in the display section 7302. Therefore, a camera including a display section with a high aperture ratio can be manufactured.

[0584] Here, although the camera 7300 has a structure that allows the lens 7306 to be detached from the frame 7301 and exchanged, the lens 7306 and the frame 7301 can also be formed as one unit.

[0585] By pressing the shutter button 7304, the camera 7300 can capture still or moving images. Alternatively, the display unit 7302 can be equipped with a touch panel, allowing for video recording via touch.

[0586] In addition, the camera 7300 can also be equipped with a separately mounted flash unit and viewfinder. Furthermore, these components can also be assembled within the housing 7301.

[0587] This implementation method can be appropriately combined with other implementation methods.

[0588] Example 1

[0589] In this embodiment, the results of reliability testing on a transistor capable of being used in a display device according to one aspect of the present invention are described.

[0590] In this embodiment, two types of transistors are manufactured that use metal oxide (oxide semiconductor) as the semiconductor layer.

[0591] As Sample 1, a transistor with a bottom gate top contact (BGTC) structure was fabricated. The channel length of this transistor was set to 3.25 μm and the channel width to 2 μm. The transistor has a back gate. Both gate electrodes are made of visible light-transmitting metal oxide films. In addition, the source and drain electrodes are also made of visible light-transmitting metal oxide films.

[0592] As Sample 2, a top-gate self-aligned (TGSA) transistor was fabricated. The channel length and width of this transistor were set to 3 μm. The transistor includes a back gate electrode. The gate electrode (the upper gate electrode) uses a visible-light-transmitting metal oxide film. Additionally, the back gate electrode, source electrode, and drain electrode use metal films.

[0593] GBT (Gate Bias Temperature) stress tests were performed on samples 1 and 2 while irradiating them with light. GBT stress testing is a type of reliability testing that can evaluate changes in transistor characteristics caused by long-term use. Light was irradiated from the top of the samples. That is, during the test, light passed through the gate electrode on the top side of the visible light-transmitting metal oxide film of samples 1 and 2 and irradiated the channel region of the semiconductor layer.

[0594] In GBT stress testing, the substrate on which the transistor is formed is kept at a fixed temperature, the source potential and drain potential of the transistor are set to the same potential, and a first gate potential is provided for a certain period of time with a potential different from the source potential and drain potential.

[0595] In this embodiment, as a GBT stress test, under an environment with a sample temperature of 60°C and light irradiation (light of about 10,000 lx from a white LED), a first gate potential Vg = -30V, a drain potential Vd = 0V, a source potential Vs = 0V, and a second gate (back gate) potential Vbg = -30V are applied for 1 hour.

[0596] Furthermore, the variable used as an indicator of the variation in the electrical characteristics of a transistor is the time-dependent change in the transistor's threshold voltage (hereinafter also referred to as Vth) (hereinafter also referred to as ΔVth). Additionally, Vth refers to the Id-Vg characteristic where Id = 1.0 × 10⁻⁶. -12The value of Vg at [A]. Here, for example, if Vth is +0.50V at the start of stress and Vth is -0.55V after 100 seconds of stress application, ΔVth is -1.05V after 100 seconds of stress application.

[0597] Figure 34 The GBT stress test results for samples 1 and 2 are shown. Additionally, in Figure 34 In the diagram, the left axis shows the change in the threshold voltage of the transistor (ΔVth).

[0598] like Figure 34 As shown, the threshold voltage change (ΔVth) of sample 1 is -1.0V, and that of sample 2 is -1.1V. This indicates that samples 1 and 2 have high reliability.

[0599] The transistor manufactured in this embodiment exhibits high reliability and minimal variation in electrical characteristics even when exposed to light. Therefore, this transistor can be placed in the display area of ​​a pixel to increase the pixel aperture ratio.

[0600] Example 2

[0601] In this embodiment, transistors capable of being used in a display device according to one aspect of the present invention are manufactured and their characteristics are evaluated.

[0602] Specifically, in this embodiment, three equivalent to Figure 4 The transistor 201A shown in the figure was subjected to Id-Vg characteristic measurement, GBT stress test, and constant current stress test. Furthermore, the channel length L of the transistor manufactured in this embodiment is 2 μm and the channel width W is 3 μm.

[0603] [Transistor Manufacturing]

[0604] First, a conductive layer 291, which serves as the back gate, is formed on a glass substrate. The conductive layer 291 is formed by processing a tungsten film with a thickness of approximately 100 nm using a sputtering apparatus.

[0605] Next, an insulating layer 211, which serves as a gate insulating layer, is formed on the substrate and the conductive layer 291. The insulating layer 211 is formed by sequentially forming a silicon nitride film with a thickness of about 50 nm, a silicon nitride film with a thickness of about 300 nm, a silicon nitride film with a thickness of about 50 nm, and a silicon oxynitride film with a thickness of about 50 nm using a plasma-enhanced chemical vapor deposition (PECVD) apparatus.

[0606] Next, a semiconductor layer 293 is formed on the insulating layer 211. The semiconductor layer 293 is formed by sequentially forming two metal oxide layers (a first metal oxide layer and a second metal oxide layer) using a sputtering apparatus, and then processing the two metal oxide layers into an island shape.

[0607] The first metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 40 nm, and the second metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 5 nm. The first metal oxide layer contains CAC-IGZO, and the second metal oxide layer contains CAAC-IGZO.

[0608] The first metal oxide layer was formed under the following conditions: a substrate temperature of 130°C, argon gas at a flow rate of 180 sccm and oxygen gas at a flow rate of 20 sccm introduced into the processing chamber of the sputtering apparatus at a pressure of 0.6 Pa, and an AC power of 2.5 kW applied to a metal oxide target containing indium, gallium, and zinc (In:Ga:Zn = 4:2:4.1 [atomic ratio]). Note that the percentage of oxygen in the overall film-forming gas is sometimes referred to as the "oxygen flow rate ratio." The oxygen flow rate ratio was 10% when the first metal oxide layer was formed.

[0609] The deposition conditions for the second metal oxide layer are the same as those for the first metal oxide layer, except for the sputtering gas flow rate. Specifically, argon gas is stopped from being introduced into the processing chamber, and oxygen gas at a flow rate of 200 sccm is introduced into the processing chamber of the sputtering apparatus. Furthermore, the oxygen flow rate ratio during the formation of the second metal oxide layer is 100%.

[0610] Next, a silicon oxynitride film with a thickness of approximately 150 nm, forming insulating layer 295, is formed on insulating layer 211 and semiconductor layer 293 using a PECVD apparatus. Then, a heat treatment is performed under a nitrogen atmosphere at a temperature of 350 degrees Celsius for 1 hour.

[0611] Next, oxygen plasma treatment is performed using a PECVD device as an oxygen supply process.

[0612] Next, two metal oxide layers (third metal oxide layer and fourth metal oxide layer) that form conductive layer 296 are sequentially formed on the silicon oxynitride film using a sputtering device.

[0613] The third metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 10 nm, and the fourth metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 90 nm.

[0614] The third metal oxide layer was formed under the following conditions: a substrate temperature of 170°C, an oxygen gas flow rate of 200 sccm introduced into the processing chamber of the sputtering apparatus at a pressure of 0.6 Pa, and an AC power of 2.5 kW applied to a metal oxide target containing indium, gallium, and zinc (In:Ga:Zn = 4:2:4.1 [atomic ratio]). The oxygen flow rate ratio during the formation of the third metal oxide layer was 100%.

[0615] The film formation conditions for the fourth metal oxide layer are the same as those for the third metal oxide layer, except for the sputtering gas flow rate. Specifically, argon gas at a flow rate of 180 sccm and oxygen gas at a flow rate of 20 sccm are introduced into the processing chamber of the sputtering apparatus for formation. Furthermore, the oxygen flow rate ratio during the formation of the fourth metal oxide layer is 10%.

[0616] Next, by processing the silicon oxynitride film and the two metal oxide layers into island shapes, an insulating layer 295, which serves as a gate insulating layer, and a conductive layer 296, which serves as a gate, are formed.

[0617] Next, the exposed area of ​​semiconductor layer 293 is subjected to plasma treatment under an argon and nitrogen atmosphere to form a low-resistance region.

[0618] Next, insulating layers 212 and 213 are formed on semiconductor layer 293, insulating layer 295, and conductive layer 296. Silicon nitride film with a thickness of approximately 100 nm is formed as insulating layer 212 using a PECVD apparatus. Silicon oxynitride film with a thickness of approximately 300 nm is formed as insulating layer 213 using a PECVD apparatus. Then, a heat treatment is performed under a nitrogen atmosphere at 350 degrees Celsius for 1 hour.

[0619] Next, conductive layers 294a and 294b, serving as source and drain electrodes, are formed on the insulating layer 213. As conductive layers 294a and 294b, a titanium film with a thickness of approximately 50 nm, an aluminum film with a thickness of approximately 400 nm, and a titanium film with a thickness of approximately 100 nm are sequentially formed using a sputtering apparatus, and then the three conductive films are processed.

[0620] Next, an acrylic film with a thickness of approximately 1.5 μm is formed on insulating layer 213, conductive layer 294a, and conductive layer 294b as insulating layer 215. Then, a heat treatment is performed under a nitrogen atmosphere at a temperature of 250 degrees Celsius for 1 hour.

[0621] [Id-Vg characteristics of a transistor]

[0622] Next, the measurement results of the Id-Vg characteristics of the transistor will be explained. As the measurement conditions for the Id-Vg characteristics of the transistor, the voltage applied to the conductive layer 296 used as the gate (gate voltage (Vg)) and the voltage applied to the conductive layer 291 used as the back gate (back gate voltage (Vbg)) were varied from -15V to +20V in increments of 0.25V. Furthermore, the voltage applied to the conductive layer used as the source (source voltage (Vs)) was set to 0V (comm), and the voltage applied to the conductive layer used as the drain (drain voltage (Vd)) was set to 0.1V and 20V, respectively.

[0623] Figure 35 The results of the Id-Vg characteristic determination are shown. In Figure 35 In the diagram, the first vertical axis represents Id (A), and the second vertical axis represents the field-effect mobility (μFE (cm²)). 2 / Vs), with Vg (V) on the horizontal axis. Note that the field-effect mobility was measured at Vd = 20V.

[0624] Depend on Figure 35 It can be seen that the subthreshold coefficient (S value) is 0.15V / dec, the threshold voltage Vth is 0.13V, and μFE is 44cm. 2 / Vs. Thus, in this embodiment, a transistor with high field-effect mobility and excellent switching characteristics can be manufactured.

[0625] [GBT Stress Test]

[0626] Next, the GBT test results of the transistor will be explained. In this embodiment, as GBT stress tests, a test with a positive voltage applied to the gate (PBTS) and a test with a negative voltage applied to the gate while irradiating light (NBITS) were performed. In PBTS, the substrate forming the transistor was kept at 60°C, and a voltage of 0V was applied to the source and drain of the transistor, while a voltage of 30V was applied to the gate, and this state was maintained for 1 hour. In NBITS, a voltage of -30V was applied to the gate while irradiating 10000lx white LED light, and this state was maintained for 3600 seconds.

[0627] Figure 36 The results of the GBT stress test are shown. Figure 36 It can be seen that the stress test yielded excellent results with a threshold variation (ΔVth) of less than ±1V. It can be inferred that the excellent results obtained from the GBT stress test are due to the fact that the transistor in this embodiment, as the semiconductor layer 293, includes stacked CAC-OS films and CAAC-OS films, and has buried channels, etc.

[0628] [Constant Current Stress Test]

[0629] Next, the results of the constant current stress test of the transistor will be explained. The constant current stress test was conducted in atmospheric atmosphere and in darkness. As a constant current stress test, the conditions were maintained for approximately 18 hours with a substrate temperature of 60°C, a source potential of ground (GND), a drain potential of 10V, and a gate potential of 0.82V.

[0630] Figure 37 The results of the constant current stress test are shown. Figure 37 In the graph, the vertical axis represents the changing rate of drain current (Id), and the horizontal axis represents the stress time. For example... Figure 37 As shown, the current value of the transistor in this embodiment varies little. Since the transistor in this embodiment includes a stacked CAC-OS film and a CAAC-OS film as the semiconductor layer 293, the current value tends to vary less compared to OS transistors or LTPS transistors that do not include the aforementioned films.

[0631] Because the transistors of this embodiment have high field-effect mobility and excellent switching characteristics, they are suitable for use as transistors in drive circuits. Furthermore, because the current fluctuations of the transistors in this embodiment are small, they are also suitable for use as pixel transistors in organic EL displays, thereby suppressing brightness degradation of the display.

[0632] Example 3

[0633] In this embodiment, transistors capable of being used in a display device according to one aspect of the present invention are manufactured and their characteristics are evaluated.

[0634] Specifically, in this embodiment, manufacturing is equivalent to Figure 4 The transistor 201A shown in the figure was used, and its Id-Vd characteristics were measured. In this embodiment, the channel length L of the manufactured transistor is 3 μm and the channel width W is 3 μm.

[0635] [Transistor Manufacturing]

[0636] First, a conductive layer 291, which serves as the back gate, is formed on a glass substrate. The conductive layer 291 is formed by processing a tungsten film with a thickness of approximately 100 nm using a sputtering apparatus.

[0637] Next, an insulating layer 211, which serves as a gate insulating layer, is formed on the substrate and the conductive layer 291. The insulating layer 211 is formed by sequentially forming a silicon nitride film with a thickness of about 250 nm, a silicon nitride film with a thickness of about 50 nm, and a silicon oxynitride film with a thickness of about 5 nm using a plasma-enhanced chemical vapor deposition (PECVD) apparatus.

[0638] Next, a semiconductor layer 293 is formed on the insulating layer 211. The semiconductor layer 293 is formed by sequentially forming two metal oxide layers (a first metal oxide layer and a second metal oxide layer) using a sputtering apparatus, and then processing the two metal oxide layers into an island shape.

[0639] The first metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 40 nm, and the second metal oxide layer uses an In-Ga-Zn film with a thickness of approximately 5 nm. The first metal oxide layer contains CAC-IGZO, and the second metal oxide layer contains CAAC-IGZO.

[0640] The first metal oxide layer was formed under the following conditions: a substrate temperature of 130°C, argon gas at a flow rate of 180 sccm and oxygen gas at a flow rate of 20 sccm introduced into the processing chamber of the sputtering apparatus at a pressure of 0.6 Pa, and an AC power of 2.5 kW applied to a metal oxide target containing indium, gallium, and zinc (In:Ga:Zn = 4:2:4.1 [atomic ratio]). Note that the percentage of oxygen in the overall film-forming gas is sometimes referred to as the "oxygen flow rate ratio." The oxygen flow rate ratio was 10% when the first metal oxide layer was formed.

[0641] The deposition conditions for the second metal oxide layer are the same as those for the first metal oxide layer, except for the sputtering gas flow rate. Specifically, argon gas is stopped from being introduced into the processing chamber, and oxygen gas at a flow rate of 200 sccm is introduced into the processing chamber of the sputtering apparatus. Furthermore, the oxygen flow rate ratio during the formation of the second metal oxide layer is 100%.

[0642] Next, heat treatment is performed. The heating temperature is set to 350°C, and heat treatment is carried out for 1 hour in a nitrogen atmosphere, followed by heat treatment for 1 hour in a mixed atmosphere of nitrogen and oxygen.

[0643] Next, a silicon oxynitride film with a thickness of approximately 150 nm, forming insulating layer 295, is formed on insulating layer 211 and semiconductor layer 293 using a PECVD apparatus. Then, a heat treatment is performed under a nitrogen atmosphere at 350 degrees Celsius for 1 hour. Next, oxygen plasma treatment is performed using a PECVD apparatus as an oxygen supply process. Finally, an aluminum oxide film with a thickness of approximately 20 nm, forming insulating layer 295, is formed on the silicon oxynitride film.

[0644] Next, a three-layer conductive layer, forming conductive layer 296, is formed on the alumina film using a sputtering apparatus. Specifically, a titanium film with a thickness of approximately 50 nm, an aluminum film with a thickness of approximately 200 nm, and a titanium film with a thickness of 50 nm are sequentially formed using a sputtering apparatus.

[0645] Next, by processing the silicon oxynitride film, aluminum oxide film and three conductive layers into island shapes, an insulating layer 295 used as a gate insulating layer and a conductive layer 296 used as a gate are formed.

[0646] Next, the exposed area of ​​semiconductor layer 293 is subjected to plasma treatment under an argon and nitrogen atmosphere to form a low-resistance region.

[0647] Next, insulating layers 212 and 213 are formed on semiconductor layer 293, insulating layer 295, and conductive layer 296. Silicon nitride film with a thickness of approximately 100 nm is formed as insulating layer 212 using a PECVD apparatus. Silicon oxynitride film with a thickness of approximately 300 nm is formed as insulating layer 213 using a PECVD apparatus. Then, a heat treatment is performed under a nitrogen atmosphere at 350 degrees Celsius for 1 hour.

[0648] Next, conductive layers 294a and 294b, serving as source and drain electrodes, are formed on the insulating layer 213. Conductive layers 294a and 294b are formed by sputtering a molybdenum film with a thickness of approximately 100 nm and then processing the molybdenum film.

[0649] Next, an acrylic film with a thickness of approximately 1.5 μm is formed on insulating layer 213, conductive layer 294a, and conductive layer 294b as insulating layer 215. Then, a heat treatment is performed under a nitrogen atmosphere at a temperature of 250 degrees Celsius for 1 hour.

[0650] [Id-Vd characteristics of a transistor]

[0651] Next, the measurement results of the transistor's Id-Vd characteristics will be explained. The transistor's Id-Vd characteristics were measured by scanning at 0.2V intervals within a range of 1.6V gate voltage and 0V to 15V drain voltage.

[0652] Figure 38 The results of the Id-Vd property measurements are shown. Figure 38 In the diagram, the vertical axis represents Id / W (A / μm), and the horizontal axis represents Vd (V). From... Figure 38 It can be seen that even if Vd changes, Id remains almost unchanged in the transistor of this embodiment.

[0653] In addition, a transistor with the same structure as the transistor in this embodiment, having a channel length L of 2 μm and a channel width W of 20 μm, was manufactured. When the gate voltage Vg is 10 V and the drain voltage Vd is 5 V, the on-state current is 2.18 × 10⁻⁶. -4 A. This value is equivalent to that of an LTPS transistor. Therefore, it can be seen that by using a short channel length in an OS transistor, which is difficult to achieve in an LTPS transistor, a similar on-state current can be achieved as in an LTPS transistor.

[0654] The transistor of this embodiment has a high on-state current, making it suitable for use in drive circuit sections. Furthermore, since the transistor of this embodiment maintains almost constant Id even when Vd changes, it is also suitable for use as a pixel transistor in organic EL displays, thereby suppressing brightness degradation of the display.

[0655] [Symbol Explanation]

[0656] 10A to 10C display devices

[0657] 11 Substrate

[0658] 12 Substrates

[0659] 13 backlight units

[0660] 14 transistors

[0661] 15. Liquid Crystal Components

[0662] 16 transistors

[0663] 21-pixel electrode

[0664] 22 liquid crystal layers

[0665] 23 Common Electrode

[0666] 25 Conductive layer

[0667] 26 Insulation layer

[0668] 27. Conductive layer

[0669] 28 Conductive Layer

[0670] 29 Connector

[0671] 31 Touch sensor unit

[0672] 32 Insulation layer

[0673] 40 Liquid Crystal Components

[0674] 45 Light

[0675] 45a light

[0676] 45b light

[0677] 51 Substrate

[0678] 61 Substrate

[0679] 62 Display Section

[0680] 63 Connecting part

[0681] 64 Drive Circuit Section

[0682] 65. Wiring

[0683] 66 Non-display area

[0684] 68 Display Area

[0685] 72 FPC

[0686] 72a FPC

[0687] 72b FPC

[0688] 73 IC

[0689] 73a IC

[0690] 73b IC

[0691] 100A to 100F display devices

[0692] 110A to 110C display devices

[0693] 111 pixel electrode

[0694] 112 Common Electrode

[0695] 113 Liquid Crystal Layer

[0696] 120A to 120B display devices

[0697] 121 Protective Layer

[0698] 124 electrodes

[0699] 125 Insulation Layer

[0700] 126 Conductive layer

[0701] 127 electrode

[0702] 128 electrode

[0703] 130 polarizer

[0704] 131 Shading layer

[0705] 132 Light-shielding layer

[0706] 133a Orientation Film

[0707] 133b orientation film

[0708] 137 Wiring

[0709] 138 wiring

[0710] 140A to 140B display devices

[0711] 141 Adhesive layer

[0712] 160 Protective Substrate

[0713] 161 Backlight

[0714] 162 substrate

[0715] 163 Adhesive layer

[0716] 164 Adhesive Layer

[0717] 165 polarizer

[0718] 166 Polarizing filter

[0719] 167 Adhesive Layer

[0720] 168 Adhesive layer

[0721] 169 Adhesive layer

[0722] 201A to 201F transistors

[0723] 202A to 202C transistors

[0724] 204 Connecting Part

[0725] 206A to 206F transistors

[0726] 207A to 207C transistors

[0727] 208A to 208B transistors

[0728] 211 Insulation layer

[0729] 212 Insulation layer

[0730] 213 Insulation layer

[0731] 215 Insulation Layer

[0732] 216 Basal layer

[0733] 217 Insulation layer

[0734] 218 Insulation Layer

[0735] 220 insulation layer

[0736] 221 Conductive layer

[0737] 222a to 222d conductive layers

[0738] 223 Conductive layer

[0739] 224 signal lines

[0740] 225 Insulation Layer

[0741] 229 Conductive layer

[0742] 231 Semiconductor Layer

[0743] 231a Channel Area

[0744] 231b Low Resistance Region

[0745] 232 Impurity Semiconductor Layer

[0746] 233 Insulation layer

[0747] 242 Connector

[0748] 242b Connector

[0749] 251 Conductive layer

[0750] 291 Conductive layer

[0751] 292 Insulation layer

[0752] 293 Semiconductor layer

[0753] 293a Channel Area

[0754] 293b Low Resistance Region

[0755] 293c LDD region

[0756] 294a conductive layer

[0757] 294b conductive layer

[0758] 295 Insulation Layer

[0759] 296 Conductive layer

[0760] 900 pixels

[0761] 900s shaded area

[0762] 900t through area

[0763] 902 wiring

[0764] 904 wiring

[0765] 914 transistors

[0766] 915 capacitor

[0767] 916 Wiring Contact

[0768] 918B Display Area

[0769] 918G display area

[0770] 918R display area

[0771] 918W display area

[0772] 930LC liquid crystal element

[0773] 932BM light-blocking film

[0774] 932CF colored film

Claims

1. A display device, comprising: Display section and driving circuit section The display unit includes a first transistor, pixel electrodes, capacitors, scan lines, and signal lines. The drive circuit section includes a second transistor. The first transistor includes: First gate electrode; First gate insulating layer on the first gate electrode; The first semiconductor layer on the first gate insulating layer; The first source electrode and the first drain electrode on and in contact with the first semiconductor layer; The second gate insulating layer on the first source electrode and the first drain electrode; and The first back gate electrode on the second gate insulating layer, The second transistor includes: Second back gate electrode; The first gate insulating layer on the second back gate electrode; The second semiconductor layer on the first gate insulating layer; The third gate insulating layer on the second semiconductor layer; The second gate electrode on the third gate insulating layer; and The second source electrode and the second drain electrode are electrically connected to the second semiconductor layer. Each of the first semiconductor layer and the second semiconductor layer comprises a metal oxide. The scan line and the signal line each include a metal layer. The scan line has a region that serves as the first gate electrode. The first gate electrode has light-shielding properties. The signal line is electrically connected to one of the first source electrode and the first drain electrode. The other of the first source electrode and the first drain electrode is electrically connected to the pixel electrode. The pixel electrode, the capacitor, the first source electrode, and the first drain electrode each comprise a material that transmits visible light. Furthermore, the capacitor has a region that overlaps with the pixel electrode.

2. A display device, comprising: Display section and driving circuit section The display unit includes a first transistor, pixel electrodes, capacitors, a color layer, scan lines, and signal lines. The drive circuit section includes a second transistor. The first transistor includes: First gate electrode; First gate insulating layer on the first gate electrode; The first semiconductor layer on the first gate insulating layer; The first source electrode and the first drain electrode on and in contact with the first semiconductor layer; The second gate insulating layer on the first source electrode and the first drain electrode; and The first back gate electrode on the second gate insulating layer, The second transistor includes: Second back gate electrode; The first gate insulating layer on the second back gate electrode; The second semiconductor layer on the first gate insulating layer; The third gate insulating layer on the second semiconductor layer; The second gate electrode on the third gate insulating layer; and The second source electrode and the second drain electrode are electrically connected to the second semiconductor layer. Each of the first semiconductor layer and the second semiconductor layer comprises a metal oxide. The scan line and the signal line each include a metal layer. The scan line has a region that serves as the first gate electrode. The first gate electrode has light-shielding properties. The signal line is electrically connected to one of the first source electrode and the first drain electrode. The other of the first source electrode and the first drain electrode is electrically connected to the pixel electrode. The pixel electrode, the capacitor, the first source electrode, and the first drain electrode each comprise a material that transmits visible light. Furthermore, the capacitor has a region that overlaps with the pixel electrode and the color layer.

3. A display device, comprising: Display section and driving circuit section The display unit includes a first transistor, pixel electrodes, capacitors, a color layer, scan lines, and signal lines. The drive circuit section includes a second transistor. The first transistor includes: First gate electrode; First gate insulating layer on the first gate electrode; The first semiconductor layer on the first gate insulating layer; The first source electrode and the first drain electrode on and in contact with the first semiconductor layer; The second gate insulating layer on the first source electrode and the first drain electrode; and The first back gate electrode on the second gate insulating layer, The second transistor includes: Second back gate electrode; The first gate insulating layer on the second back gate electrode; The second semiconductor layer on the first gate insulating layer; The third gate insulating layer on the second semiconductor layer; The second gate electrode on the third gate insulating layer; and The second source electrode and the second drain electrode are electrically connected to the second semiconductor layer. Each of the first semiconductor layer and the second semiconductor layer comprises a metal oxide. The scan line and the signal line each include a metal layer. The scan line has a region that serves as the first gate electrode. The first gate electrode has light-shielding properties. The signal line is electrically connected to one of the first source electrode and the first drain electrode. The other of the first source electrode and the first drain electrode is electrically connected to the pixel electrode. The pixel electrode, the capacitor, the first source electrode, and the first drain electrode each comprise a material that transmits visible light. Furthermore, the capacitor has a region that overlaps with the coloring layer.

4. The display device according to any one of claims 1 to 3, wherein each of the first back gate electrode and the second gate electrode comprises an oxide conductor.

5. The display device according to any one of claims 1 to 3, wherein the first semiconductor layer comprises In-M-Zn oxide, and M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, Sn or Hf.

6. The display device according to any one of claims 1 to 3, wherein each of the first source electrode and the first drain electrode comprises an oxide conductor.

7. A display module, comprising: The display device according to any one of claims 1 to 3; as well as Circuit board.

8. An electronic device, comprising: The display module as described in claim 7; as well as At least one of the following: antenna, battery, housing, camera, speaker, microphone, and operation buttons.

Images